Commercial fishermen fear a recent decision by MAF Biosecurity to allow imports of Vietnamese catfish could cripple the industry.
The Federation of Commercial Fishermen says the market for New Zealand hoki dropped by 90% when the species was imported into Australia.
About 1200 inshore fishermen operate out of coastal ports in New Zealand and the federation says they will struggle to compete with cheap imports.
Federation president Doug Saunders-Loder says imported Vietnamese catfish is likely to be supplied to supermarkets and fish and chip shops at half the price of New Zealand products.
The federation says it also has concerns about the quality of Vietnamese catfish, which is farmed in the Mekong River.
It is calling for the fish to be labelled so consumers know its place of origin.
Mr Saunders-Loder says labelling is not required in New Zealand, but it should be mandatory.
He says Vietnamese catfish would not look dissimilar to New Zealand favourites such as snapper or tarakihi once processed as fillets.
Commercial fishermen and fish markets say they do not expect catfish to be popular, as it has a muddy taste.