"It is the responsibility of the food operators to ensure the sale of safe and suitable food," he said.
"The inspections and verifications undertaken by the council ensure that the businesses are meeting this responsibility."
Nando's New Zealand general manager Garth Parker told Fairfax the store replaced the benchtop and a pest control company was called in.
Staff had also cleaned out the whole store following the closure.
"This was an isolated case and there has been no impact to the safety of our customers," he said.
Parker said all the other 13 Nando's outlets in Auckland were A-grade.
The restaurant has to wait 90 days for re-grading, but Parker said he was confident the council would reinstate the A-grade status.
The US based fast food outlet has more than 30 stores around the country. Nando's International purchased the master franchise licence for the business in New Zealand in May 2014.
Founded in South Africa in the late 1980s, Nando's arrived in New Zealand in 2000 when the first store opened in Glenfield on Auckland's North Shore.