New Zealand's Parliament has entered into the matter of a Malaysian diplomat implicated in the sexual assault of a New Zealand woman, with its Labour Foreign Affairs spokesperson David Shearer calling for an urgent debate.

Shearer, as reported by TVNZ, questioned Foreign Affairs Minister Murray McCully over the ministry's handling of the issue and said the victim has been denied justice as the accused has returned to Malaysia.

McCully (right) admitted to the legislature that there were several shortcomings in the case.

"It is something that is not denied by members of this side of the House," McCully reportedly said.

Armed Forces officer Muhammad Rizalman Ismail, attached with the Malaysian High Commission in Wellington, was in May charged with burglary and assault with the intent to rape a 21-year-old woman in her house in Wellington.

However, it was later disclosed that the accused was repatriated to Malaysia following informal discussions between the two governments and that Rizalman is being investigated by the Malaysian military.

Earlier this week, New Zealand Prime Minister John Key said Malaysia rejected its request to waive Rizalman's (left) diplomatic immunity so that he could be put on trial in New Zealand, after being charged in May.

The New Zealand Foreign Affairs Ministry has just apologised to its government over the mannerin which it handled the diplomatic immunity case.

Official did not know Rizalman left

Radio New Zealand reported the Ministry of Foreign Affairs and Trade's chief executive John Allen as saying he did not know, until last Friday, that Rizalman had been allowed to leave the country.

Allen today apologised to the government and the alleged victim for the way in which the ministry handled the case.  

TVNZ further reported that Allen met McCully this morning to acknowledge the shortcomings in the advice provided by the ministry and the manner it managed the incident.

"The ministry has fallen well short of its obligations to the government on this occasion and we take this failure very seriously," Allen said.

"Unfortunately, the way the ministry dealt with this issue left some ambiguity around our position - which was that the accused should face justice in New Zealand," he is quoted as saying, adding the ministry was initiating a review process to reassess its policy and procedures in handling similar situations.

The ministry, Allen said, is likely to appoint an independent reviewer for this task.

Warrant issued for arrest of Rizalman

McCully said the talks his ministry had with Malaysia led to the Malaysian government to thinking New Zealand was happy for Rizalman to return to Malaysia and be held accountable there.

TVNZ further reported that the New Zealand police have issued an arrest warrant for Rizalman in relation to both charges.

The police there are continuing their work and the Ministry of Foreign Affairs and Trade is considering all options to achieve the best outcome for the victim and for justice.

This includes extraditing Rizalman, and the ministry is establishing a legal foundation for this.