Trustpower chief executive Keith Tempest says the next step in setting up the 20 turbine, 32MW windfarm will come early next year, when the Trustpower board further considers the project.

The South Australia windfarm has already been under development for more than two years, with the planning application being "called in" and formally declared a "major project" by the South Australian state government.

Tempest said other wind projects in South Australia were also being investigated.

Trustpower is currently more than doubling the size of its Tararua farm near Palmerston North - the biggest in Australasia - from 32MW to 68MW, with the first of the new turbines due to start delivering power from next month, with the last due to be installed in next May.