The Green Party is calling for a referendum on asset sales as soon as possible, and say it could be held early next year, before any of the power companies are sold.
The party is in the Keep Our Assets coalition, which has collected 240,000 signatures as it strives to get the 310,000 needed to trigger a citizen's initiated referendum.
The coalition launched a drive today aiming to collect the remaining signatures by the end of next month.
"A referendum early next year is a real possibility," said Greens co-leader Russel Norman.
"If we have the required number of signatures by the end of September, Parliament's Clerk of the House can validate the petition by the end of November."