Anglers have been increasingly reporting catching snapper with milky flesh and are worried about the risks of eating the fish.

LegaSea wrote on Facebook it had received a number of enquiries about the safety of eating or touching milky flesh snapper caught off the northeast coast of the North Island.

"Please keep an eye out for any milky flesh fish. It's important for all of us to know what the cause is and how it will be addressed."

Auckland angler Nate Sampson told RNZ the fillets are mushy.

"On Sunday my wife, our son and I brought home our entitlement of 32cm to 42cm fish and when I had filleted them I noticed that two of the fish were in skinny condition with milky white coloured flesh.

"It was so mushy, was damn near impossible to fillet", Sampson said.

A Fisheries New Zealand spokesperson said the issue appeared to be prevalent in the Hauraki Gulf and East Northland areas.

"The Ministry for Primary Industries (MPI) has tested samples of the milky-flesh fish and has not found any evidence of food safety risk, nor have they received any reports of associated illness," they said.

"As a precaution, MPI will continue to monitor and conduct further testing. If any food safety issues are identified, MPI will take action to protect and inform the public."

The testing has also not detected any disease or parasites in the fish but further sampling and testing would be done as a precaution.

Fisheries New Zealand is working to establish the cause of the milky-fleshed fish, including whether changes to food sources, climate effects, and environmental and ecosystem conditions may be playing a part.

LegaSea said the New Zealand Sport Fishing Council has submitted an Official Information Act request to Fisheries New Zealand with the hope of finding out what information there is on the situation and what will be done to address the problem.