About 600,000 New Zealanders go fishing every year.

Recreational fishermen face reduced daily bag limits, increased size limits and seasonal bans unless New Zealand's fisheries are better managed, a new report says.

The report by think tank The New Zealand Initiative said New Zealand has some of the most relaxed recreational fishing rights in the world but new management ideas are needed in order to keep it that way.

Author Dr Randall Bess said the depletion of some fish stocks and increases in New Zealand's population and tourism numbers meant fishing would increasingly come under threat.

About 600,000 New Zealanders go fishing every year, but New Zealand has no recreational ocean fishing permits or reporting requirements and generous bag limits.

This was not sustainable for a population projected to increase from 4.7 million to 6 million by 2060, he said.

READ MORE: Hauraki Gulf and Marlborough Sounds fishing parks are a political power play

"Minimum size increases and reduced bag limits means catching legal-sized fish is becoming increasingly difficult," Bess said.

Stringent catch limits and seasonal restrictions, like those implemented in the Marlborough Sounds blue cod and scallop fisheries, could be replicated in other regions, he said.

In recent decades significant change had also been imposed on the Snapper one region which covers the east coast between North Cape, 30 kilometres east of Cape Reinga, and Cape Runaway, 90 km northeast off Whakatane, out to a distance of 370 kilometres.

The daily bag limit reduced from 30 snapper in 1985 to the current limit of seven snapper set in 2014 while the legal size limit had increased from 25 centimetres to 30 centimetres.

Last year the Government announced plans to create recreational fishing parks in the inner Hauraki Gulf and the Marlborough Sounds, and compensate commercial fishermen for the loss of their catch in those areas.

The way total catch was allocated between commercial and recreational fishermen was a highly politicised process with lobbyists pressuring the Government to allocate more of the total catch for their particular interests, Bess said.

"New Zealand needs a robust system where the catch allocation decisions are not politicised to the extent they are currently."

There was also an underlying problem of complacency in recreational fisheries management and a lack of fisheries policy leadership and technical competence, he said.

"This hands-off management approach is not sustainable, as growth in New Zealand's population and tourism further increases the demand for recreational fishing."

The institute's next report would investigate international best practice and policy recommendations to enhance the recreational fishing.

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