AC/DC drummer Phil Rudd has made a surprise guilty plea to charges of threatening to kill and drug possession at the opening of his trial in New Zealand.

Rudd had previously denied all allegations against him, but changed his plea on the first day of the trial at Tauranga District Court.

As a result, judge Robert Woolff adjourned the hearing after just ten minutes and extended Rudd's bail until a sentencing hearing on 26 June.

Threatening to kill carries a potential jail term of seven years, but Rudd's solicitor Craig Tuck said the 60-year-old would apply for a discharge without conviction at the sentencing hearing.

Rudd was arrested in September at his waterfront mansion in the town of Tauranga on New Zealand' North Island, with court documents revealing he was accused of threatening to kill a contractor and his daughter.

Police also found 0.71 grams of methamphetamine and 130g of cannabis when they raided the property, the documents said.

Rudd initially faced another charge of "attempting to procure murder", but it was dropped after prosecutors decided there was insufficient evidence to proceed.

The identity of the people threatened has been suppressed by the court.

Australian-born Rudd, who has lived in New Zealand since 1983, said nothing to the waiting media, in contrast to previous appearances when he had made rude gestures to reporters.

His legal problems have threatened his position with AC/DC, although last year he vowed to return to the rock group's line-up.

Chris Slade - the band's drummer in the early 1990s - has replaced Rudd in recent appearances and is set to play on AC/DC's upcoming "Rock or Bust" world tour.