Whitebaiters on the West Coast want the season there aligned with the rest of the country.
The West Coast season is a month shorter than elsewhere.
In Canterbury, the whitebaiting season began on 15 August - two weeks before the season on the West Coast.
Fishermen there say poachers take advantage of this by illegally catching whitebait in West Coast waters and then selling it in Canterbury and other areas where the season is under way.
They say the whitebaiting season should start and finish on the same dates in every region.
However, the Department of Conservation doubts claims that a longer season elsewhere than on the West Coast is creating a market for illegal catches.
The department's ranger for the Hokitika area, Ted Brennan, says he does not know why poachers would take a trip to the coast to fish illegally.
Mr Brennan says the season has to start later on the West Coast to give whitebait a good chance to run up the rivers to breed.