The Auckland terrorist's immigration history is a glaring omission in the review of events leading to the 3 September attacks, according to the National Party.
Charities say services offered to asylum seekers also need reviewing, because huge gaps in services are exacerbating the trauma new arrivals feel after escaping their home country.
It's two weeks since Ahamed Samsudeen stabbed shoppers at a supermarket in New Lynn.
The government on Thursday announced a review covering three of his 10 years in New Zealand - the second period he spent in custody and since he was released.
It will look at the actions of police, Corrections and the SIS in their dealings with Samsudeen and its primary focus is the period leading up to his release in July and the seven weeks before the attack.
The scope of the inquiry specifically excludes immigration, decisions taken before his latest period in custody and the legislation which agencies operate under.
"The biggest piece of the jigsaw was completely left out," said opposition immigration spokesperson Erica Stanford. "Immigration really is the key to finding out why this guy was still in New Zealand and why he wasn't deported. And that is a big bit that's missing.
"He applied for refugee status not long after he arrived, and there are certainly questions around how he was granted that refugee status - why he was declined, why he was granted it by the Immigration and Protection Tribunal, what evidence was supplied, and how much investigation was done into his claims by the IPT, which were eventually found out later, as we now know, not to be correct."
Other issues to explore included why his deportation appeal was delayed, if he could have been detained in the meantime and whether he received adequate mental health and settlement support, she added.
"If you read the IPT report it clearly states that this young man had severe depression, even before the post-traumatic stress and those things that caused the post-traumatic stress so he is obviously a deeply troubled young man right from a very early age," she said.
"They knew that and there needs to be questions asked as to what sort of wraparound services we then put around him to keep him safe and also our community safe."
'Gap in the system' for asylum seekers
Labour MP and former refugee Ibrahim Omer spoke in parliament during the terrorist attack debate, stressing he did not want Samsudeen to adversely affect other asylum seekers who come to New Zealand.
"The last few months we've been working around asylum seekers because we identified a huge hole and the gap in the system and in the way that asylum seekers are being supported.
"We've heard that this guy had a severe mental health issue and now, in our system asylum seekers get very little support around the mental health and other support."
Charities told RNZ many asylum seekers were left anxious, vulnerable and traumatised by their experiences in New Zealand.
Samsudeen arrived in 2011 and it was two years before he was accepted as a refugee.
The Asylum Seekers Support Trust had no dealings with him and its general manager, Tim Maurice, said it was not clear if Samsudeen got any support at all.
The early experiences of "convention refugees" - those who successfully seek asylum after they arrive here - are starkly different from the 1500 annual quota refugees, he said, who receive orientation, English language classes and housing.
"Practically on the ground, quota refugees get the six-week resettlement training programme at Māngere refugee centre, they get support from the Red Cross for one year, although with Covid that's been extended to two years.
"And convention refugees unfortunately, they get a letter saying 'congratulations you've been accepted', and just in the last couple of years they've started to get one phone call from a desk-bound immigration worker just checking in are they ok, 'how's things going?'."
Some struggle to get work rights or a benefit, and the Auckland charity runs a hostel as many cannot afford accommodation.
While some asylum seekers found his organisation, or support through existing refugee networks such as Falun Gong, many were not so lucky.
"Others are left all alone and they just try and survive by themselves and they have no support," he said. "It's really difficult in a new country, often escaping from trauma and problems ... to try and resettle without language skills and support.
"Often a lot of the trauma that refugees are facing in New Zealand comes from their experiences inside New Zealand.
"They've come here looking for a safe place to live and they get granted permission to stay here, but then they're expecting to be able to get a job, get a house, resettle with their family and there's blockages all the time for that to happen."
About half of the 500 a year asylum seekers are eventually recognised as refugees, he said.
The trust is calling on the government to include convention refugees in its resettlement services strategy and to have an independent review.
"If we did a proper review and we looked at what other countries do and look what's happening here we'll soon figure out a little bit of money spent early on to help people resettle will have huge outcomes for these people and for our country.
"We want people engaging in our communities, contributing to our communities. It's very hard to do that when you're stuck at home, no English skills and no-one able to provide you with the education to be able to increase your English skills or to be able to get a job."
Asylum seekers were navigating a strange country, sometimes unaware of their rights and when they were rejected - for example, an MSD staffer not knowing they were eligible for emergency benefit - they would accept that and stop asking for help.
Convention refugees also face protracted wait times for permanent residence, while refugees automatically have that status on arrival.
A human rights leader at the Wellington Community Justice Project, Amandie Weerasundara, said its asylum seeker equality project has not been able to pinpoint the reason the two groups are treated differently.
"They'll need to be reliant on either support from an organisation like the Asylum Seeker Support Trust or whatever sort of funds they've been able to bring with them," she said. "And the length of time between the claim and interview has been growing and growing in the last couple of years.
"People who are successful at the first claim still don't have much support from immigration and beyond that point you're kind of on your own to figure out what you're going to do in New Zealand."
It contributed to asylum seekers feeling stigmatised, as though the quota was the only legitimate way to be a refugee in New Zealand. If they were not hooked into service providers it could lead to delays in receiving mental health treatment because full state-funded health care only came with residence.
"Some of these people may be detained by the immigration authorities upon making their claim, for arriving in New Zealand on false pretences so it is quite a stressful situation, and there's a lot of uncertainty for people in this process."
The government announced in July a review of the policy of detaining some asylum seekers - an average of 10 a year - in prison, mainly at Mount Eden in Auckland. That followed a report by Amnesty international into the practice, detailing the rape of a man who later was recognised as a refugee, and coercion by criminals into taking part in flight clubs.
Work was already underway to bring the level of services in line with those provided to quota refugees, said Omer.
He is working with the Associate Minister of Immigration Phil Twyford on a review of detention of asylum seekers in prison.
Isolated and poverty-stricken
Refugees As Survivors has a team of 40 working at the Māngere centre and in a mobile service.
"They'll definitely have all suffered some sort of psychological trauma from the aftermath of whatever the overwhelming force was that happened in order for them to become either refugees or asylum seekers," said its chief executive Sharron Ward.
"They have fundamental issues, things that we take for granted - the need for safety and autonomy and control, and the most important need is to be attached and have a connectedness. And that's the difference between them and quota refugees, who get a wraparound service and they get a home and they get benefits."
It made them stressed, needy and poverty-stricken, and although the asylum claims process was improving since a report two years ago, there was much left to do.
"It is a long, arduous process, and there's definitely room for improvement. I'd say 50 percent of our mobile service at the moment is dealing with those anxieties of people who are still trying to claim asylum in New Zealand.
"The process is definitely not easy - the waiting times, the access they have and lack of facilities and the lack of benefits is appalling - housing, children going to school, all of that. What we can't do is just isolate them and leave them in ghetto kind of situations where they fall through the gaps."
A doubling of funding would improve the charity's resources and nationwide access, she said.
Immigration NZ defends support it offers
Immigration New Zealand (INZ) said in a statement it would explore the inclusion of convention refugees during a "refresh" of the 2012 refugee resettlement strategy, but that would not cover asylum seekers given their undetermined refugee status.
It said it provided information to asylum seekers about the process and services they can access and a welfare advisor can assist them.
"This includes connecting them to government services such as healthcare, including funded mental health services, financial support, housing and education," said INZ'S general manager of refugee and migrant services, Fiona Whiteridge.
"In general, on receipt of a claim, an adult asylum seeker who is able to work is eligible to apply for an asylum work visa. There is no general requirement that the decision on the visa is only made after the person attends an interview with a refugee and protection officer.
"The typical length of the initial visa is 12 months. A work visa enables the asylum seeker to find work to support themselves as they are going through the process. Should they not be able to find work or otherwise support themselves, they are also entitled to access a benefit - this includes income support and emergency benefits."
Asylum claimants were only detained as a last resort, such as after being refused entry on their arrival because of their previous travel or criminal history, or owing to their identity not being established.
"Convention refugees do receive settlement support and are provided help to link them to services including health, employment and education in the community. They also have access to the driver training programme and the refugee employment programme as well as language support.
"Refugees and protected persons are eligible to apply for permanent residence and New Zealand citizenship after five years of residence. They may be eligible for a work visa while they are waiting for their residence visa application to be decided."