As many as 800 Auckland eateries will operate with an expired food grade from today - and another 121 are still waiting for checks more than six weeks after opening.
Auckland Council has moved to reassure consumers about the situation it calls "unprecedented".
They say restaurants are caught in a verification backlog created by the introduction of the Food Act 2014.
A look at the Auckland Council's online listings for food businesses in Ponsonby - one of the city's premiere dining districts - revealed a little less than one-third would be operating under an expired or "grade pending" status today.
High-profile restaurants and bars including Bedford Soda & Liquor, Revelry, Longroom and Saan are among those apparently caught in the verification backlog.
Mervyn Chetty, manager environmental health said about half of the Ponsonby businesses "have actually been verified" but records had not been updated.
Citywide, the situation was less clear: "We would need to manually look at the record for each individual businesses . . . we can tell you that approximately 800 premises' grades will expire. However we are unable to say how many have re-registered at this point."
He said "we foresee no adverse impact on public health" and said existing grades issued under the former Food Hygiene Regulations were valid until new ones were issued.
"We do not believe there is any significant public health risk . . . most of our food operators understand the importance of producing safe and suitable food, and the majority of our businesses are A grades.
"We are facing an unprecedented and significant shift in the way food safety is managed in New Zealand . . . there have been some challenges along the way."
Under the new law, eateries opened before March 2016 were given three years to switch from the council's inspection regime to a new "risk-based" verification system.
Auckland's 1400 highest-risk food businesses had made the shift by the first deadline of June last year.
However the second stage of the transition, due to be completed today, involved 3500 businesses - and many had only started the transition in the last three months.
"Inevitably, with a high demand for a service all at once, this has created a backlog for the council's Environmental Health team," Chetty said.
Seven environmental health officer vacancies had been filled in the last six months to "address these challenges".
There are 10,000 registered food premises across Auckland, including 619 that are new since June last year.
Chetty said 183 of those new premises had yet to receive their first verification, with 121 waiting more than six weeks.
In some instances, businesses had yet to open, had requested a delay, or, in up to 60 per cent of cases, Council had yet to schedule a visit.
Two restaurants contacted by the Weekend Herald, who didn't want to be named, confirmed they had been in communication with Auckland Council about the expiry of their grade and were waiting for an inspection.
Another two eateries said Auckland Council health officers had been by to inspect their premises.
Staffers at these establishments said they had received a grade, and were surprised to hear the expiry date of their grade had not yet been updated online.
The owner of one newly-opened restaurant, which had been in operation since February this year, said he had not yet heard from Auckland Council.
The Restaurant Association of New Zealand's chief executive officer, Marisa Bidois, said she had heard from the management team at two Auckland restaurants about the delays.
The situation would be frustrating, she said, whether restaurants were waiting for an initial grade to be issued or for a new grade to be updated online.
"If you are a business and for whatever reason you've been given a lower grade and you have the opportunity to remedy the situation and be checked again… that would be the situation I can imagine most business owners would be very keen to have resolved quickly."
"That's the livelihood of a business... you want the opportunity to be able to reassure your customers about the standard of the business."
It was not ideal for a new business to be stuck on a "pending" grade either, Bidois said.
"You're trying to build a reputation, you're trying to put your best foot forward… and it could potentially be affecting the business."
Chetty said the widespread delays could largely be attributed to the change in system.
"This is the biggest change to the food safety landscape ever seen in New Zealand," said Chetty.
Council was managing two food safety systems during the transition period, and while businesses were keen to comply, "there are a number who are finding it difficult to understand the changes they need to make".