Commercial fishermen in the northern Kaipara Harbour have been warned their boats will be blown out of the water unless they abide by a Government ban on fishing that expired six weeks ago.

The ban, or rahui, was imposed by local Maori at Tinopai in 1997 and received Government endorsement three years later, but only until June this year. The Government has refused to extend it, although it has yet to produce a promised fisheries management plan for the harbour.

Fisheries Minister Pete Hodgson is awaiting a report from a fishing study group set up to develop a management strategy.

Some fishermen have already defied the rahui, which extends over 15 square kilometres between Tinopai and the Puketotara Peninsula, known locally as The Funnel.

The Kaipara, the largest harbour in the Southern Hemisphere, has been the scene of angry confrontations over fishing rights for more than a decade.

Shots have been fired, fishing gear stolen and cars, boats and trailers vandalised.

Some of the best fishing grounds in the harbour are regarded as no-go areas by commercial fishermen, even though there is nothing in law to stop them fishing there.

Tension peaked at Tinopai after the rahui was imposed. Fishermen defied it and were threatened by angry locals.

Police at that time called public meetings and threatened to lock up any fisherman caught with a gun on board and prosecute anyone who escalated the situation.

There was relative peace after the Government backed the rahui in June 2000 with fines of up to $100,000 for fishing commercially.

Now there are signs the situation will explode again.

"If any commercial fishing boats are caught fishing in the Tinopai rahui area they will be blown out of the water," Waiaotea Marae rangatira Mikaera Miru said yesterday.

"I'm not saying I'm going to do it, but someone is going to get hurt. This is a serious bloody issue."

At Ruawai, fisherman Dave Salter said he would abide by the rahui, but did not agree he should have to.

"I've had $5000 worth of gear stolen; I've been threatened."

Last year his boat was deliberately rammed in another part of the harbour, near Otamatea Marae.

Another Ruawai fisherman, Chris Matich, said he had fished in the Tinopai rahui area since June, but added: "I would tell people not to antagonise the locals. If you put nets out there [in front of Waiaotea Marae] you deserve to get them pinched."

The pressure would come on in a few weeks when the dogfishing season began. Mr Matich agreed there were other parts of the harbour that everyone avoided because of threats and attacks from Maori with gang connections.

Mr Miru said he saluted his "cuzzie bros" at Otamatea who had kept commercial operators out of their area by intimidation.

"We've been through the right channels and tried to do everything by the book and we've been shafted."

His own opposition began in 1991 when "out of frustration" he took a shotgun down to the beach and began firing it in the air to warn boats off.

Since then, others had taken direct action, while he had got involved with the politics. But members of his own iwi, Te Uri o Hau, part of Ngati Whatua, had ignored the three Tinopai marae's wishes on fisheries management and endorsed a Ministry of Fisheries plan for the Kaipara that he said would do nothing to reduce commercial fishing pressure on the harbour, particularly in areas of traditional cultural importance.

"Some of these fishermen have no idea, no respect.

"Why do we have to go through this hysterical bullshit to get decent management in this country? We need to talk, to end the racial tension.

"In Tinopai we've got a plan, but we're being ignored."

He said 231 locals signed a petition to Mr Hodgson asking that the rahui continue for two more years.

"If anyone gets hurt, the buck stops with him."