Labour criticised by environmental groups for promise to keep Tiwai Point smelter open

Labour's promise to keep the Tiwai Point smelter open comes as welcome relief for Southland - but the move is being criticised by environmental groups.

Labour's joining National in promising to negotiate an extra three to five years before the smelter shuts down. It says it'd do that by supporting Transpower to lower power costs.

However Jacinda Ardern is being accused of "buckling under pressure" from Rio Tinto to do a deal.

Any deal would come with conditions for Rio Tinto.

The company would have to clean up the site, stay open for an agreed time, and maintain employment.

"We will all benefit from having additional time and a managed exit from Tiwai Point," Ardern said on Monday.

"What we are asking is that Transpower will go into negotiations with Rio Tinto around the way that they deploy their line charges."

Tiwai is the backbone of the Southland community. People here are pleased to see the big parties vowing to keep it open a bit longer.

But there's criticism from others with a Greenpeace statement accusing Labour of "buckling under pressure".

"Rio Tinto just keep coming back and back and back and back and back for more and more taxpayer subsidies and it looks like it's going to get away with it again," Greenpeace executive director Russell Norman told Newshub.

"There's no question this is a corporate handout, this is how Rio Tinto lives."

And Greenpeace climate and energy campaigner Amanda Larsson said in the statement Rio Tinto is being subsidised for its climate emissions and is refusing to take responsibility for its impact on the environment and local communities.

"We're in the middle of a climate crisis and Rio Tinto has been given a free pass to spew climate pollution into the atmosphere," she said.

"The smelter also needs to start paying for its carbon pollution, like other companies do."

But Ardern denies she's buckling to pressure from Rio Tinto.

"Absolutely not," she told Newshub. "Now what we're doing here is making sure that we have an opportunity for our workforce to transition to new opportunities that include the potential for green energy."