The director of a new documentary on overfishing says Australia needs to act now to protect its fish stocks or it will suffer dire consequences.

Rupert Murray is in Sydney to promote the film The End of The Line, which premiered at the Sundance Film Festival and opens to Australian audiences in April.

The film warns that 70 per cent of global stocks are now in trouble and there could be no seafood by the middle of the century unless practices change.

He says the depletion of fish stocks worldwide is a major environmental problem.

"The reason why I made the film is I love eating seafood," he said.

"I want the oceans to be full of fish and [be] healthy and beautiful. I want there to be a viable fishing industry as well. I want there to be recreational fishing.

"But if we continue on the way we're going, all of that is going to end."

Murray says Australia must keep watch, with 16 species already overfished.

"Overfishing is one of the biggest environmental problems, but it's the one that people know the least about," he said.

Government action

The Federal Government is considering setting up marine sanctuaries along the Australian coast, which Murray says are urgently needed.

Only 5 per cent of Australia's coastline is protected and environmental groups want the Federal Government to take note of Murray's message.

WWF biologist Gilly Llewellyn says the Government must act now.

"This year, this is the time that we need the Government to put its hand up to be a leader in marine conservation and put in large networks of no take zones for that region, and for the whole of the rest of Australia," she said.

The seafood industry acknowledges the problem, but warns the documentary focuses on overfishing in Europe, the United States and Asia.

Brian Jefferies from the Commonwealth Fisheries Association says there is no doubt that many countries are facing overfishing problems.

But he says Australian fisheries are much better run.

"The issue in Australia is fisheries management has been around for a lot longer - over 50 years," he said.

"In Europe it's been there for three or four years - that's the difference. And we've got into a position in Australia where things are stable and improving all the time."

Audiences can make up their own minds when the film opens in Australia in April.