Prime Minister John Key says he will not speculate on the reasons behind an arson attack at his electorate office in Auckland.
Detectives are investigating who threw a bottle filled with a flammable liquid into the property, which is in a residential area at Kumeu, at 3am on Thursday. A small fire caused minor damage.
Mr Key says staff at the office are shocked by the attack. He says there had not been any warning or threats beforehand, but it might now be necessary to review having extra security there.
Police say it is too early to comment on whether it was a random attack.
In 2004, an axe attack was made on the electorate office of former prime minister Helen Clark in Auckland.