A brick was thrown at Prime Minister Helen Clark's Auckland office early today in a protest against the Electoral Finance Act.
The attack at the Mt Albert electoral office happened around 12.30am, with the offender seen disappearing on a scooter immediately afterwards.
The window was cracked but not broken.
An email from a lobby group, People Power, claimed the brick was thrown in protest against the Electoral Finance Act, which came into force today.
People Power describes itself as a stand alone, non-politically affiliated citizens lobby group that wants to see democracy returned through the repealing of the Act.
The new law has caused heated debate, with opponents claiming it is a restriction on free speech in election years. A general election must be held by November 15 this year.
Police northern communications spokesman Inspector Ian Brooker said a woman who witnessed the attack possibly prevented further damage through her actions.
The woman, a local resident, had been watching midnight fireworks when she noticed a cat wandering near the office at about 12.30am. Knowing that a neighbour had lost their cat, she went to have a closer look.
At the same time she noticed a person on a motor scooter, who had a short time earlier ridden up the road, stopped and thrown a brick at the window of the electorate office.
"As she went closer to try to get the registration number of the scooter, she was attacked by the cat and screamed. Both the cat and the motor scooter rider were alarmed and left at speed," Mr Brooker said.
The woman, who wishes to remain anonymous, called police and supplied them with descriptions of the offender and his scooter.
Civil Liberties spokesman Barry Wilson said the group should not remain anonymous.
He said the lobbyists lack credibility unless they show their faces and such acts are misguided.
"If they've broken the window in Helen Clark's office the taxpayer will be paying so they should at least be prepared to pay the cost of the window, front up in court and most of all, say exactly who they are," Mr Wilson said.
A Christchurch-based training company called People Power, which has contracts with government departments and the police, was today anxious to stress it had no connection to the protestors.
Director Erenie Papageorge said: "I don't know who these people are and wish to disassociate my company and myself from anything to do with this incident."
It is the second time the Prime Minister's Electoral Office has been targeted by vandals. Right-wing activist Tim Selwyn took to the office with an axe in November 2004.
He was later jailed for willful damage, publishing a seditious statement about the act and fraud.
- NZPA, NEWSTALK ZB, NZ HERALD STAFF