The Prime Minister says the opposition has conned the public by presenting a petition to Parliament with 100,000 invalid signatures.
A coalition promoting the petition to stop asset sales has two months to get an extra 16,000 signatures needed to force a referendum.
To force a referendum, the petition needed to have been signed by 10% of eligible voters - about 308,000.
When presented, the petition had 392,000 signatures, but 100,000 were not deemed valid.
John Key says the parties should apologise for misleading the public and repay the money they used.
The Green Party says it used $91,000 of its Parliamentary budget because it wants New Zealanders to have a say on asset sales.
The Labour Party says its only spending was staff time coordinating travel and organisation.
The parties say the Prime Minister has spent $1 million selling taxpayers something they already own.
