THE Federal Government is to spend $7 million on finding a way to clean up the now defunct Rum Jungle uranium mine.

The Australian Greens revealed the clean-up move in a Senate Estimates hearing -- four decades after the mine was closed.

Senator Scott Ludlam said the money would be spent over four years to determine how to deal with the toxic legacy. He said it was unacceptable the Government could not tell taxpayers what the final cost would be.

The Territory's mining sector had been plagued with problems as a result of under-regulation, he said.

Ranger uranium mine, which is in Kakadu National Park, had suffered more than 150 leaks, spills and licence breaches since the mine opened in 1981, he said.

In 2009, a government-appointed scientist said Ranger's tailings dam was leaking 100,000 litres of contaminated water every day. This was denied by ERA.

Federal Resources and Energy Minister Martin Ferguson said there were comprehensive safeguards to manage the Ranger mine.

"Rehabilitation costs are fully funded in advance by the private sector,''  he told the NT News.

"It is totally inappropriate to compare the operations of 40 years ago with the safeguards in place today.''

He said Rum Jungle was owned by the Federal Government and Canberra was "going about the job'' of rehabilitating the site.