Voters are set to be bombarded by record levels of advertising during the next election, after Government moves to relax some campaign spending rules.
In a big change to the former Electoral Finance Act, National is proposing to allow lobbyists, such as unions or special interest groups, to spend any amount during election campaigns – provided they register with the Electoral Commission and identify themselves in their advertisements.
The move could see a return to the sort of high-spending negative campaign run against the Greens by the Exclusive Brethren during the 2005 election. In addition, lobby groups will be able to advertise for as well as against political parties – raising the possibility of "back door" donations that get around the limits on what politicians can spend.
There will also be no limit on how much can be spent by campaigners on the referendum on MMP, which will also take place at the next election.
But the advertising can only take place in non-broadcast media, after the Government decided to keep current limits on broadcasting during campaigns in place.
Political parties will continue to be limited, but their spending thresholds will still increase by the rate of inflation since the 2008 election. That is likely to take the limit from $2.24 million today to about $2.4m, or an increase of about $168,000.
Labour's justice spokeswoman Lianne Dalziel said though National's proposals would identify parallel campaigners, they would not stop lobbyists working closely with political parties to tilt the financial playing field.
"This still risks creating the sort of free-for-all that occurs in the United States, where campaign spending is out of control. New Zealand has campaign spending limits and we must keep it that way."
Ms Dalziel said Labour feared that the Exclusive Brethren could again enter the election campaign.
"Labour's Electoral Finance Act was a direct response to the subterfuge and political chicanery that characterised parallel campaigning in the 2005 election. Exclusive Brethren members were behind a secret parallel campaign on a scale never before seen in New Zealand," she said.
The Greens also strongly oppose the move to remove spending caps.
"It is vital that New Zealand's democracy cannot be bought by big business. An election should be a battle of ideas, not a battle of who has the most money," said Russel Norman, Green Party co-leader.
"New Zealand runs the danger of ending up like the US, where the elections are awash with money, and lobby groups can buy influence."
Members of the Exclusive Brethren involved in the anti-Green campaign in 2005 did not return calls yesterday.
Justice Minister Simon Power also released details of the referendum on the electoral system, including the wording that will be put to voters.
Voters will first be asked whether or not to retain the current MMP system. They will then be asked which system they would choose instead. If voters choose to change the electoral system, a second referendum will be held in 2014.
The Campaign for MMP welcomed the announcement, but criticised the decision not to impose spending limits on next year's referendum.
Spokeswoman Sandra Grey said the lack of a "level playing field" was a concern.
"All general elections and citizen-initiated referendums have had strict election spending controls to ensure a fair and democratic process. So why are there no spending controls at all for the MMP referendum?"
But anti-MMP campaigner Peter Shirtcliffe, who spearheaded the original fight against changing the electoral system in 1993, said he did not plan to spend a lot of money this time.
He said he had spent "a king's ransom" at the time, fighting in what he described as a "filthy" campaign.
But times had changed and people had matured, he said.