Auckland Council is apologising for issuing several A-grade restaurants with D food grade ratings.
The council last month said 25 Auckland eateries have been given D or E ratings, with those on the worst ratings being made to close down until they fix the problem.
Reasons for the ratings include poor pest control, cleaning, cooking processes and food storage.
However, the council has accepted that it had this month wrongly graded at least two restaurants, and the Herald understands there may be a third.
"Auckland Council in early February inspected two businesses in Meadowland [in Somerville, east Auckland] that had previously been given D grades," said Mervyn Chetty, manager environmental health, Auckland Council.
"Unfortunately D grade certificates were sent to these businesses in error, as our system was not updated with the new grades in time."
Chetty said replacement certificates with the correct grades were sent out to the restaurants as soon as the council was made aware of this error.
"We apologise to the businesses for our error and we will be taking steps to minimise the chance of this happening again in the future," added Chetty.
Businesses which have been given a D rating would be re-inspected within two months of the grading.