Storm in a teapot transforms New Zealand's sleepy election season

John Key’s embarrassing remarks in a café were recorded (AP)

It was a lacklustre election campaign whose result seemed a foregone conclusion: victory for the New Zealand Prime Minister, John Key, at the polls this Saturday. Then a freelance cameraman left a tape recorder running on a café table where Mr Key was meeting an ally, unleashing "Cuppagate" – a row about politics, privacy and media ethics.

Bradley Ambrose says he inadvertently left the device behind, inside a bag, following a photo-opportunity with Mr Key and John Banks, an ACT party candidate. The Prime Minister, however, has complained to police that a private conversation, held over a cup of tea, was illegally recorded, and has accused the media of "UK-style News of the World tabloid tactics".

Neither the Herald on Sunday newspaper nor the TV3 channel, both of which have copies of the "teapot tape", has released its contents. But Winston Peters, leader of the rival New Zealand First party, who appears to have a transcript, claims the two men criticised the ACT leader, Don Brash, and made disparaging remarks about New Zealand First's ageing supporters.

It's hardly sensationalist stuff, and – despite dark hints by the Herald on Sunday – is unlikely to alter the election outcome. But the row has dominated the headlines, frustrating Mr Key's crusade to paint himself as a safe pair of hands at a time of economic uncertainty, as well as attempts by the opposition leader, Phil Goff, to win over voters by dyeing his hair and donning motorbike leathers.

This week police are expected to execute search warrants on the Herald and TV3, as well as two news organisations that interviewed Mr Ambrose about "Teapotgate". Mr Ambrose, for his part, has accused Mr Key of defaming him. Tomorrow he is going to court to seek a ruling on whether the café conversation was private.

Opinion polls suggest Mr Key's centre-right National Party, which has governed in coalition with ACT and two smaller parties since 2008, will win an outright majority. Nevertheless, the Nationals may need ACT, and the event in the Auckland café was designed to encourage voters to support Mr Banks.