The Australian government wants to preserve the reef's rich marine life

The law will ban fishing in one third of the World Heritage Site's 345,000 sq km area, and leave tourism as the only permitted industry.

The ban comes in response to concerns that overfishing is depleting the reef's rich marine life.

The reef is home to sharks, turtles and numerous brightly coloured fish.

This is going to mean bigger fish for tourists to come and see David Kemp Australian environment minister

Federal environment minister David Kemp said ending overfishing would make the coral reef more able to withstand other damaging influences, such as global warming and soil swept down rivers after heavy rain.

"It is a quite remarkable advance in protecting the reef against all the pressures to which it's subject," he said.

"This is going to mean more fish on the Barrier Reef, healthier corals - it's going to mean bigger fish for tourists to come and see."

GREAT BARRIER REEF More than 2,000 km long Home to 1,500 types of fish Only living thing the naked eye can see from space

There will also be tougher limits on the movement of shipping in the area off Australia's north-east coast.

Mr Kemp said anyone caught breaching the regulations would face heavy penalties.

Compensation

WWF Australia has hailed the plan, which was submitted to parliament last December, as a "dramatic improvement".

But environmental groups urged the government to police the new zones properly to ensure fishing vessels do not encroach into protected areas.

The commercial fishing industry has warned that the plan - which is has been fighting for the past four years - could devastate some operators and the small communities that rely on them.

The government has said assistance will be given to fishermen, including the buying-out of licences and redirecting them into other careers.

"We haven't specified any particular sum of money, but we intend that this shall be dealt with in a very fair way," he said.

There are other factors that damage the reef - chemical run-offs from cattle grazing, sugarcane growing and urban development.

The Great Barrier Reef, situated off Queensland state in north-east Australia, injects an estimated A$1.5bn ($975m) into the economy each year through tourism and fishing.