Cabinet ministers will today consider whether any law changes are needed following Friday's terror attack, but some MPs are warning against any knee-jerk reactions.
Ahamed Aathill Mohamed Samsudeen was shot dead by police on Friday after stabbing six people inside Countdown LynnMall - a seventh person was also injured.
At the weekend it was revealed that the government spent years trying to deport the man and wants to plug any gaps in the law.
Samsudeen applied for refugee status just a month after arriving in New Zealand in 2011, which was granted after an appeal process in 2013.
By 2018 work was underway for him to be stripped of that status and deported, with officials believing documents he had provided were fraudulent.
At the weekend Deputy Prime Minister Grant Robertson explained how difficult the deportation process had been.
"Throughout the large part of this period, the terrorist was actually in prison, and therefore the deportation process stopped until that had changed.
"If we were to change that there is a very significant move and would need quite a lot of consideration," he says.
Waikato University international law professor Alexander Gillespie says the terrorist should not have been allowed to remain in the country as long as he did.
"This is outrageous ... this is where the big mistake has been, because even if the person has refugee status, they do not have a right to stay in the country if they are a national security threat. And so long as it goes through the courts with due process, that person should be exited.
"This is where we need to put all of our effort right now," he said.
Green Party immigration spokesperson Golriz Ghahraman is apprehensive of any law change that will make it easier to deport someone who is granted refugee status.
"We're actually doing something that's pretty serious and pretty-knee jerk in terms of whether it would ever have addressed any of the issues that come about when we're talking about radicalisation here in New Zealand. It's, it's really missing the point and doing something that's dangerous," she said.
She said the focus should be on rehabilitation rather than immigration status.
National's immigration spokesperson Erica Stanford said her party supports any changes that would have helped prevent this attack, but she is unsure which parts of the law need to change.
"I've spoken with a number of experts and immigration lawyers, and even they're a little bit stumped. It is a very difficult situation that we're in in regards to refugees especially and being able to deport them because of the special recognised status that they have."
The Crown tried - and failed - to charge Samsudeen under the Terrorism Suppression Act because planning to commit a terrorist attack is not an offence under current law.
The prime minister is promising to fast-track new counter-terrorism laws - which National supports.
However, ACT's David Seymour was not convinced this would be the best course of action.
"A much more sensible response would actually be to take more time to ensure we are solving any problems that we are now aware of due to these events."
Seymour says his party is proposing three law changes, including balancing the protection of a "protected person" with the threat they pose to New Zealand and the ability to detain those awaiting deportation or those who cannot be deported due to international obligations.
He also wants the preparation of a terrorist attack to be a crime.
Massey University terrorism expert Dr John Battersby said the current terrorism laws are no longer fit for purpose and he says planned changes to the legislation do not go far enough.
He wants police to have more power to keep those who pose a threat like Samsudeen away from the public, which could include incarceration, even without the need for prosecution of a crime.
"What we need to be able to do is be able to exert some control over people who are clearly exhibiting extremism, exhibiting a desire to want to carry attacks out. We need to be able to get some control over them in trying get them into rehabilitative programmes to guide them away without an offence committed without them necessarily being prosecuted for anything."
Dr Battersby says this was a "draconian way to go", but that is the direction that officials need to start considering.
However, he warns regardless of any law changes there is no guarantee a security or legal system will stop a terrorist attack.