Rio Tinto is talking to Japanese energy companies over the potential sale of its 68 per cent stake in Energy Resources Australia (ERA), which owns the Ranger uranium mine in the Territory.

Sources close to the company said Rio was considering a sale of its controlling interest in its group-wide effort to slash debt. Ranger is the second-largest uranium operation in Australia and accounts for 11 per cent of global output.

"Rio has received several expressions of interest from Japanese companies involved in power generation," the source said. "It's at an early stage but Rio is now testing that interest."

The NT Environment Centre said the sale of ERA should not lead to any attempt to overturn the opposition to the neighbouring Jabiluka project by traditional owners.

Spokesman Justin Tutty said this would "reawaken" a strong campaign.

Rio is open to selling the ERA stake as it is likely to attract a premium price for the business.

ERA enjoyed one of its strongest years on record last year, boosting profit almost 200 per cent to $221.7 million. With such emerging economies as China embracing nuclear power, Rio will have little difficulty selling Ranger.