Whitebait caught from sewage-contaminated rivers could end up on the plates of unsuspecting diners at restaurants and cafes, the New Zealand Food Safety Authority (NZFSA) warns.

Whitebaiters are continuing to fish from contaminated Canterbury rivers, river mouths and estuaries following last month's earthquake, despite warnings that their catches could cause serious illness.

NZFSA acting deputy director general of food safety, Carol Barnao, said it was disappointing the whitebaiters had not taken the warnings seriously.

"Our concern is whitebaiters are selling their catch, which is most likely contaminated, to unsuspecting restaurants and cafes."

Cafes and restaurants have been asked to double-check the origin of whitebait, as West Coast catches have been quite low this season.

Both proprietors and whitebaiters could be held liable for any food-borne illnesses caused by contaminated whitebait.

Canterbury health officials have indicated they would ask Civil Defence to use its powers to have police remove whitebaiters from contaminated rivers if the warnings continued to go unheeded.

Failing to comply with a Civil Defence order could lead to a fine of up to $5000 or three months' jail.

- NZPA