An Australian tourist man has been left rueing a drunken domestic fracas in Queenstown that soured his two week New Zealand holiday and cost him about $1880.

Dean Shane Cowan, 40, who works as a labourer for a council in Townsville, today pleaded guilty in Christchurch District Court to assaulting his partner of five years in an altercation that had the neighbours phoning the police.

Duty defence solicitor Tony Garrett said the extra cost of staying on for the court hearing, extra hire car costs, and rebooked flights had cost Cowan about $1000.

Then Judge Gary MacAskill fined him $750 and ordered him to pay $130 court costs.

Police prosecutor Nigel Wolland described the Friday incident in which Cowan and his partner were both drunk and returned separately to their hotel room.

His partner came back first and went to bed, but when Cowan arrived he found himself locked out and had to get staff to let him into the room.

The couple then argued and Cowan poured water over his partner in bed, and punched or slapped her hard enough on the side of the face to perforate an eardrum.

The woman went out on the balcony to smoke a cigarette and Cowan locked her out there. She screamed to be let back inside and neighbours called police.

Cowan was abusive toward the officers but they dropped a charge a of resisting arrest when he pleaded guilty to the assault.

He told police he had just locked his partner outside and had not done anything wrong.

Mr Garrett acknowledged Cowan had behaved childishly by locking out his partner.

"This should have been a pleasant ending to a two-week holiday in New Zealand," Mr Garrett.

He said the pair had managed some sort of reconciliation.

The woman had already flown home and Cowan would fly out on Wednesday when he has settled his fine, and been given back his passport.

Judge MacAskill told Cowan: "You need to understand that any form of violence, whatever the circumstances, is unacceptable. The fact that you were both drunk is not a mitigating factor."