Mercury says it wants to build a new $115 million, 43 megawatt wind farm at Kaiwera Downs, south of Gore.

Auckland-based Mercury said it had executed contracts for the procurement and construction of the first stage of Kaiwera Downs.

The company said the project would lift Mercury's total financial commitment to new renewable wind generation to almost $600m since 2019.

"This wind farm is part of a significant renewable growth pipeline for Mercury, with several other renewable projects under investigation," chief executive Vince Hawksworth said.

"Mercury is committed to supporting New Zealand's decarbonisation goals and one of the most meaningful ways we can do this is through building and supplying more renewable power," he said.

"Stage 1 of the Kaiwera Downs Wind Farm is the next cab off the rank in our pipeline of new renewable generation," he said.

Mercury's $480m Turitea Wind Farm in the Manawatū is nearly finished.

"We have an outstanding pipeline of renewable generation projects," Hawksworth said.

"Our decision to proceed with Kaiwera Downs is an exciting next step, and by no means the last," Hawksworth said.

The 10 turbines to be constructed as Stage I of the Kaiwera Downs Wind Farm will add enough new renewable power to run 66,000 electric vehicles.

A second tranche of the build will complete the 240MW consented on the site as the transition to a lower carbon economy progresses.

Hawksworth said New Zealand needed more renewable generation up and running.

"The electricity sector's investment in new renewable generation has a key role in enabling New Zealand's transition to a low carbon future, with the country on track for over 90 per cent renewable electricity in the next three to five years," he said.

Mercury has become New Zealand's biggest wind power generator.

Last year, Mercury's wind generation produced 1,269 gigawatt hours of power.

That will increase as Turitea South comes onstream, with Kaiwera following in late 2023.

Turitea Wind Farm is scheduled for completion mid 2023, and will be New Zealand's largest wind farm.