A baby formula company has used photoshop to add an image of Mr Key into an advertisement without his permission.
Mr Key said the photo was taken when he opened the Cowala baby food factory in Auckland in June - the company that wholesales baby food products to other seller.
"It's no great drama on one level," he said on Radio Live this morning.
"The problem is basically the Cabinet manual prohibits it."
He posed for photographs and signed some tins of baby formula.
A spokeswoman for the Prime Minister told the Herald on Sunday it was "disappointing" that Key's image had been used without approval.
"The advertisement is misleading as it implies the company's product has an endorsement from the Prime Minister, which it does not.
"The Prime Minister's office will be writing to the company to ask them to desist from their actions."
Cowala is a subsidiary of GMP Pharmaceuticals and exports its baby formula to China, Japan and Korea.
Chief executive Karl Ye said the advert had been created by one store, and he had told the store to remove the advertisement. "We didn't have anything to do with making this advert."
Mr Key said it wasn't the first time his image had been used without authorisation - he appeared in a lumberjack outfit on another occasion.
- Kate Shuttleworth of APNZ
