Legal advice suggests any enforced use of the passports in a domestic setting could be open to challenge under human rights law.
RNZ understands officials could be on uneven ground if they tried to make Covid-19 vaccination passports mandatory in places like restaurants and bars, or at events such as rugby games or concerts.
As such, any moves regarding vaccine certificates will see the onus put on business owners, who will be left with a moral decision around whether to serve people without verification of vaccination.
Restaurant Association chief executive Marisa Bidois said that would be unfair on small businesses.
"Some of the major concerns that businesses have in this discussion were the fact that they would have to manage the process for this," Bidois said.
"I think it is a lot to ask for a small to medium business owner or any business for that matter, to potentially police this sort of system."
Bidois said support for mandatory vaccine certificates to access restaurants has waned over the past two months.
Before Auckland's current lockdown, about 70 percent of restaurants surveyed said they broadly supported a vaccine passport system, but that has dropped to 50 percent support more recently.
"Many were quite reluctant to implement something like this unless it was mandated, you know, unless they weren't required to do so.
"Some, however, have jumped on board and we've seen there are some business owners who are supportive of this and it's something that, some are looking at ways that they may be able to implement it in their business right now."
Sherridan Cook who is a partner at Auckland law firm Buddle Findlay said forcing the use of vaccination passports in a domestic setting seems unlikely.
He said it could be done, but the big question from a legal perspective is the risk posed by patrons.
"The Bill of Rights Act in New Zealand doesn't have the status of overriding other legislation," Cook said.
"The government is supposed to act in accordance with the Bill of Rights Act when it legislates for things like this. But it can't be used to strike it down, like in the US where the US Constitution could be used to strike down legislation.
"There could still be challenges perhaps by people under the Bill of Rights Act, but again, it comes back to well, is this a justified limitation on people's freedom of movement?"
Sources RNZ has spoken to say a mandatory vaccination certificate framework could end up similar to that of the mandatory scanning rules in place across the country.
While Prime Minister Jacinda Ardern has framed it as being compulsory for people to scan or sign in at businesses for contact tracing purposes, there is no such law for individuals.
The law only states that businesses must provide people with the ability to scan or sign in.
Businesses do not have to force people to sign in.
Cook said a similar rule would make sense given the current threat of the virus, and that would put the onus on business owners.
"At the moment, in this kind of foreseeable future that, well, we might not be too bad, it's going to be down to businesses.
"And some of those will make it a marketing step, they'll be saying come to our shop or whatever because, you know, everyone who works here is vaccinated and we only let in people who are."
Where to get a vaccination in Auckland - without a booking
The Ministry of Health's national digital services manager, Michael Dreyer, said the My Covid Record service will be released to the public by the end of the year.
He said the vaccine certificates will comply with international standards, and will most likely take the form of a QR code that can be scanned and verified.
That throws up further issues for businesses, like how they would be expected to scan such documents, and if that would have to come out of their own pockets.