The Northern Territory mining union says workers are worried that Rio Tinto's expected plans to sell off Northern Territory interests will mean more job losses and worse pay and conditions.

Rio Tinto is expected to announce today it will sell its 68 per cent stake in the Energy Resources Australia (ERA) uranium mine at Jabiru, and part of its bauxite mine and aluminium refinery at Gove, to pay off a 37 billion dollar debt.

Matthew Gardiner from the Liquor Hospitality and Miscellaneous Workers' Union says the main interested buyers for the ERA stake appear to be overseas companies, and Federal foreign ownership rules would stop a single overseas interest taking the lot.

The Union says workers at Alcan are covered by a collective agreement, but falling demand for bauxite and aluminium could threaten job security under any new owner.

"We've seen what has happened in the other parts of the mining industry, with companies going under left right and centre, and selling off, and laying off staff, at an unprecedented rate," Mr Gardiner said.

The Northern Territory's Resources Minister, Kon Vatskalis says he'd be very surprised if jobs were lost at Jabiru.

"My understanding is Japan is very hungry for energy," he said.

"I don't think there would be a severe impact on ERA Jabiru operations because Japan will still need the uranium for the nuclear power stations that they posses and operate.

"But I'll be waiting with interest to see what's going to happen."