Anyone who is double-vaccinated for Covid-19 will be able to request a vaccination certificate later this morning.
The certificate, dubbed "My Vaccine Pass", will be required in a range of public settings under the new traffic light system.
"People will need one to do a lot of the things they're looking forward to doing over the summer," Covid-19 Response Minister Chris Hipkins told Morning Report.
"It will be a very, very important part of the traffic light system because [the pass] will differentiate between what the unvaccinated and the vaccinated can do in order to keep everybody safe."
The settings that will require proof of vaccination include events, hospitality, community, sport and faith-based gatherings.
Retail outlets are allowed to opt in to the new system and request proof of vaccination from their customers if they wish.
"The Ministry of Health has worked closely with businesses and events companies to ensure they have the technology solutions needed to verify the pass - which will become part of people's daily routine, like carrying a driver's licence, scanning in at the supermarket or wearing a mask."
Access to essential services like supermarkets, pharmacies, dairies, all health services and petrol stations will not require a pass.
"To get [My Covid Pass], people will need to be fully vaccinated or be one of the very small number of Kiwis who has received a medical exemption," Hipkins said.
The free passes, issued by the Ministry of Health, could be requested by logging in to the website My Covid Record or calling 0800 222 478.
My Vaccine Pass was the only official government pass and Hipkins told people to be wary of imitations.
My Vaccine Pass will have a QR code that can be downloaded onto your phone, stored in your Apple or Google Wallet or printed out in hardcopy.
Hipkins said those who were not comfortable using online technology or smartphones would be able to call the 0800 number and have their pass sent to them, and arrangements were also being made for places where people could drop in to have their vaccine passes printed.
He said more information about those options would be made available in the coming days.
More than 3.4 million people are double-vaccinated and would be able to request their My Vaccine Pass today but Hipkins said people should wait if they could to ease demand on the IT system and call centre staff.
"The system is pretty good, it's pretty robust. It can produce about 200 vaccine certificates per second and I'm told by industry standards that's pretty good, but of course if we get everybody all logging in this morning ... any system's going to find that a bit overloading.
"You won't need them in the next day or two so spread it out over the next couple of days and the system should be able to cope with that."
A process was being put in place for the vaccination status of those who had been immunised overseas to be recognised in New Zealand, Hipkins said.
Proof of a booster shot is not currently required for My Vaccine Pass but the certificate will only be valid for six months from its issue date.
Retailers seek clarity on vaccine certificates
Retailers want to know the legal standing of businesses that opt to require vaccine certificates as a condition of entry, and whether that extends to staff as well.
Retail NZ chief executive Greg Harford told Morning Report there were still some grey areas to work through around the implementation of vaccine mandates for retail staff in businesses which opted to use vaccine passes despite not being legally required to.
"I know lots of businesses are looking at mandating the vaccine for their staff., he said.
"Obviously if they're a hospitality business or another business where the vaccine pass is a specific requirement, those staff will need to be vaccinated, but there is an unusual interface with employment law here, where businesses need to go through really solid processes ... before they can put mandatory requirements in place."
"That potentially exposes employers to the risk of a personal grievance, which is absurd in the circumstances and something we think government needs to fix legislatively."
Harford said retailers were also concerned about staff being asked to police the rules preventing unvaccinated people from entering a business premises.
He said that had led to "some pretty nasty situations for retail workers to deal with".
"We understand the need for some of these rules - what's important I think is that ... the legal obligations sit on the customer and that there's a really clear pathway for the police to become involved if people don't want to comply, or become abusive."