The Clerk of the House of Representatives today confirmed a petition, organised by the Keep Our Assets coalition, had attracted 327,224 signatures - about 18,500 more than required to force a citizens initiated referendum on asset sales.
The petition is due to be tabled in Parliament tomorrow, after which the Government will have a month to set a date for the referendum, or declare a postal referendum.
Mr Key said the referendum would have to be held by September 3 next year, but he was still taking advice on when it should take place.
He said the non-binding referendum - likely to be a postal vote at the cost of $9 million - would be a waste of money.
"We had a referendum - it's called a general election, and National won that election on the back of this major policy plank with an overwhelming majority, the biggest result we've received in MMP history," he said.
"It's a complete and utter waste of money because it's just about sending a message."
Asked if he would ignore the referendum result, Mr Key said it might be too late because the mixed-ownership model programme was already going ahead.
He would not postpone the Government's float of Meridian Energy until the referendum was held.
"I think it will be fairly politically driven anyway - the turnout is likely to be relatively low, and those that vote are more likely to be those who are opposed."
Green Party co-leader Russel Norman said the referendum should take place as soon as possible, and argued that the partial sale of power companies should be suspended until the vote was held.
He defended the cost of the referendum, which Mr Key said could be between $9m and $30m.
"Let's put it in perspective - the Government has spent over $100 million already on an asset sale programme which is extremely unpopular," Dr Norman said.
Labour's state-owned enterprises spokesman Clayton Cosgrove said the asset sales programme, including the Meridian float, must be halted until after the referendum.
"John Key must respect the democratic process. Over 327,000 Kiwis have called for a referendum. Their voice must be heard," Mr Cosgrove said.
The Keep Our Assets coalition had two months to collect 16,000 valid signatures after the initial count was deemed just short of the 308,753 required.
After a thorough checking process, it was estimated that 327,224 eligible electors had signed the petition.
The petition, led by Grey Power president Roy Reid, asked: "Do you support the Government selling up to 49 per cent of Meridian Energy, Mighty River Power, Genesis Power, Solid Energy and Air New Zealand?"
The Speaker is expected to present the petition to the House tomorrow.
The date of the referendum must be within a year of its presentation to the House, unless the House - by a 75 per cent majority vote - agrees to postpone it for up to a further year.
