The national horticulture industry body thinks the Ministry for Primary Industries should be doing more to police the labelling of irradiated tomatoes from Australia.
The Government changed the import rules earlier this year to allow imports of Australian tomatoes and capsicums that have been irradiated for pest and disease control.
The treated produce has to be labelled as such.
Horticulture New Zealand chief executive Peter Silcock says he understands supermarkets are not selling Australian tomatoes at the moment because they still have good supplies of locally grown tomatoes.
However, he says the organisation is finding fruit and vegetable sellers at farmers markets who are breaking the labelling law.
Mr Silcock says some of those selling at markets are labelling well, but others have no labels at all to indicate the product has been irradiated.
He says they should have received information from the people they are buying from to indicate whether the product is irradiated or not.
Mr Silcock says Horticulture New Zealand has informed the Primary Industries Ministry and asked it to follow it up when it has become aware of breaches of the regulations.
He says it would like the ministry to take a more active policing role to ensure people are complying with the law around labelling of irradiated tomatoes from Australia.