The Northern Land Council says Xstrata has behaved rudely to traditional owners by informing them of plans to expand McArthur River Mine three days after telling the market.

The NLC says traditional owners were only told yesterday of Xstrata's plan to extend the zinc mine's life to 2033.

Xstrata told the media and the stock market about the plans on Friday.

NLC chief executive Kim Hill says the company should have talked to traditional owners first.

"It's quite rude for Xstrata to announce to the faceless shareholders of Xstrata what their intentions are, but go back 72 hours later and tell the community this is what we are intending to do."

The NLC is also calling on the Territory Government to stop allowing mining companies to self regulate.

Mr Hill says Energy Resources of Australia is ignoring traditional owners' concerns that its radioactive tailings dam at the Ranger uranium mine is almost full.

He says traditional owners want water diverted into the mine pit for safety, even though ERA says there is no danger of a spill into Kakadu National Park.

"It just demonstrates that you can't trust miners to monitor themselves and the Territory Government definitely needs to step in," Mr Hill said.