Cabinet is working to determine how widely they will be used and more information will be made available in a few weeks.
Prime Minister Jacinda Ardern said the Government still needs to iron out the details on other critical aspects, including the rules for individual businesses that want to use the certificate to turn away customers.
"How do we create a legal framework where we haven't mandated but someone wants to use it? How do we create a legal framework for them to be able to if it's within certain parameters?
"There are some areas where we would want to be very explicit, that you should never withhold services that are essential: food, access to health services, pharmacies and so on."
The Government is talking to the hospitality industry but some cafes and restaurants have already stated they do not want to ban unvaccinated customers or staff.
Greg Harford from Retail NZ said compulsory use seems unlikely in his sector although there are businesses who like the idea.
There are also those who would struggle to enforce a ban - that's why he would like them to have a choice.
"The biggest thing the Government can do to help in this space is to explicitly give businesses the power to require their staff to be vaccinated, if the employer thinks that's required. That could also extend to customers.
"What's important is every business is able to make its own decision on these issues."
He also wanted much clearer detail on what will be considered an essential service that cannot turn unvaccinated people away.
"There has been significant confusion around what constitutes an essential product at various alert levels. I think as long as the Government is clear about what it is defining as essential for the purposes of vaccination certificates, that will help resolve some of those issues."
Grey Power apprehensive over tech issues Jo Miller from Grey Power is worried about those who may struggle to use the technology to download a certificate.
"I do think the Government has a responsibility to make sure, even if they ask for assistance or help to do it, but to make it easier for those sorts of people to be able to access it so that they feel free to go out and about and that if they want to go to summer events with their family they can comfortably go."
Dr Andrew Chen, an expert on digital technology, said the certificate system was first and foremost paper-based with an app as an add-on for convenience.
"The app is just to improve convenience, in that you have one less piece of paper to carry around. Hopefully, that won't exclude too many people.
"Anybody who needs a certificate will hopefully be able to go to a library or Citizens Advice Bureau or find a family member who can help them register for My Covid Record and then generate and print a certificate for themselves if they need one."
But he is worried about what it all means for those who have legitimate medical reasons for not being vaccinated.
"It may be safer for someone who is immunocompromised, for example, to not go to a festival but you want to make sure that they can still participate in society and not live in a second class of society. So we need to hear a bit more about how the system will be managed for those people."
The Government is set to release further details in the coming weeks.