The Green Party has used $75,000 of taxpayer money to pay signature-collectors for a referendum opposing asset sales.
The party has used its Leader's Office fund to hire the equivalent of eight fulltime staff members in an attempt to force a citizens-initiated referendum before the Government begins to sell state-owned power companies.
The payments were permitted under parliamentary rules, but it was believed to be the first time the fund has been used to gather support for a party policy.
The Greens spent $47,000 of their annual leader's fund to pay signature collectors in Auckland, Hamilton, Wellington, Christchurch and Dunedin, and planned to spend around $76,000 in total.
Communications director Andrew Campbell said the party was proud to spend part of its $1.3 million leader's budget to fight asset sales, and would consider the strategy again.
"Compared to other campaigns who might spend hundreds of thousands of dollars paying pollsters ... we would rather use the leader's budget to campaign on issues we feel are important to New Zealand."
He added: "This amount is a drop in the bucket compared to the $120 million the Government is going to spend on investment banks and PR firms to sell our assets."
Parliamentary Service general manager Geoff Thorn said that the Greens' spending was within the rules because they were not asking the public for votes, membership or money.
Mr Thorn said the people collecting the signatures were not Parliamentary Service employees, and engaging contractors was within the definitions of what Leaders Office money could be used for.
Electoral law expert Graeme Edgeler said that while the Greens' strategy was allowed, he did not feel it was appropriate.
"The reason that we give parliamentary parties money is so that they can keep us informed of what they're doing so that they can effectively do their jobs in Parliament.
"Using the money as a direct funding of people to go out and get signatures is a step more than any other party has done to date, and that might be a little concerning if it is seen to be appropriate."
When political parties' spending was reviewed in 2010, Mr Edgeler asked for use of Leader's Office money on gaining support for a referendum to be banned.
"If you're not allowed to tell people to vote a certain way in a citizens-initiated referendum, why can you spend money telling them to sign their name on a petition to get a referendum? It seems an odd distinction."
Prime Minister John Key and Leader of the Opposition David Shearer refused to comment on the Greens' spending.
The Keep Our Assets petition was launched last month by a coalition of Labour, the Greens, Grey Power, the Council of Trade Unions, Greenpeace, and the Union of Student Associations.
The coalition needed 310,000 signatures to force a referendum - a tenth of the voting population. It was aiming to hit the target by September. The Greens have gathered 41,600 names so far, with 20,000 coming in the last week alone.