The National Party has attacked the Green Party over its use of taxpayer money to collect signatures for a referendum on asset sales - but has not ruled out doing the same for its campaigns.
The Greens' use of public money to pay signature collectors was permitted by parliamentary rules, but it was believed to be an unprecedented use of the Leader's Office fund.
Finance Minister Bill English criticised the spending during parliamentary question time yesterday.
"It is a bit odd that Greens used to support citizens-initiated referendums, whereas now we are paying for Greens-initiated referendums."
National MPs backed Mr English with cries of "shame" and "pay it back".
Greens co-leader Russel Norman responded, saying his party had been transparent about its spending, while the Government had refused to reveal how much it had spent on "spin doctors", advertising and banking fees in the sale of state-owned companies.
The Green Party committed $76,000 of its Leader's Office fund to fight the Government's asset sales. The party clarified yesterday that $47,000 of this was used to pay people to collect signatures to force a referendum.
Asked if he could rule out National using the fund in a similar way, Mr English said: "As far as I understand it's not against the rules. But I think everyone needs to know that the petition they're signing is run by the Greens and funded by the taxpayer."
The annual leader's fund is allocated according to the size of the party - the Greens had $1.3 million to spend a year - and can be used only for parliamentary purposes.
The money cannot be used to publish material to gain votes, membership or money.
Speaker of the House Lockwood Smith was not consulted on the spending, but said asset sales were an issue that was before the Government and taking action to oppose it might be considered a parliamentary purpose.
The Greens were paying the equivalent of eight full-time staffers to collect signatures over eight weeks, and also recruited 2000 volunteers.
They wanted to collect the required 310,000 signatures and prompt a referendum before the Government's proposed sale of Mighty River Power in the third quarter of the year.