Milk products sold in Asian supermarkets in New Zealand were being tested for the contamination which has killed four Chinese babies and put thousands of others in hospital.
The New Zealand Food Safety Authority said it was testing dairy and milk products for melamine, the additive which was put into Chinese milk products, the New Zealand Herald daily reported on Saturday.
Food safety inspectors began taking random samples on Thursday night from Asian supermarkets.
The authority initially focused on infant formula, said deputy chief executive Sandra Daly.
"We have primarily been testing infant formulas because they are at the high risk, but we are now looking to identify other dairy products which may also be affected," she told the paper.
She said New Zealand did not import infant formula directly from China, but imported very small amounts of dairy products such as milk, milk powder and cheese. The checks were a precautionary measure.
She said there was no reason to recall any products the authority had tested.