THE world's largest producing uranium mine is about to get bigger after a new deposit has been found in Kakadu National Park.

Energy Resources Australia has found up to 40,000 tonnes of uranium oxide located next to the Ranger open-cut mine in Jabiru, 260km east of Darwin.

Recent exploration has found the possibility of an underground mine east of Ranger - with a potential of 20 million tonnes of minerals, including 30,000 to 40,000 tonnes of uranium oxide.

But Mining Minister Kon Vatskalis said any mine expansion would be subject to a strict approval process.

The Northern Land Council said all activity at the mine must be subject to the "highest degree of scrutiny".

Ranger mine produces 11 per cent of the world's uranium. The expansion could see the mine operating for another five or six years.

NT Resources Council chief executive Scott Perkins said China's plans to build more than 20 nuclear power plants had created a strong market for uranium.

"We know there is a lot of uranium in the ground in the Northern Territory," he said.

"The real question is the market value it will have."

BHP Billiton recently announced the expansion of the Olympic Dam mine in South Australia, which will see the production of 1.6 million tonnes of copper concentrate and 19,000 tonnes of uranium.

"We know there is a marketplace for these things and the NT is in a good position to take advantage of this," Mr Perkins said.