A Labour weekend sting by fisheries officers caught "multiple" people illegally taking blue cod, including undersized catch, in the Marlborough Sounds.
The Sounds closed to blue cod fishing in December last year and is due to open again in December.
In a statement, the Ministry for Primary Industries said "the overall compliance rate was poor".
It said it was "disappointing" that among those caught was a charter vessel - with 30 blue cod filleted on board - knowing full well that it was illegal.
Federation of Commercial Fisherman president Doug Saunders-Loder said tough rules applied to the commercial sector and everyone had to play.
'We've got a golden egg here in the context of New Zealand fisheries, and we just have to make sure we don't mess that up.
"Commercial, recreational or customary, we're in the same tent and it's about recognising our impacts and its about working together in a responsible way," Mr Saunders-Loder said.
The Ministry said "multiple infringement notices" were issued during the Labour weekend operation.