The United States government has refused to waive immunity for a diplomatic staffer at its New Zealand embassy.
Police said the staffer was involved in an incident at a house in Lower Hutt in the early hours of Sunday morning, but left before they arrived.
The Ministry of Foreign Affairs and Trade (MFAT) was asked by New Zealand police to request a waiver of diplomatic immunity from the US, so the police could question the staffer as part of their investigation.
But today the US declined that request, and the ministry has subsequently asked for the staffer to be withdrawn from New Zealand.
In a statement, the US Embassy said any allegations of wrongdoing were always fully investigated and it was in touch with New Zealand authorities.
"As a matter of policy, we do not comment on the specifics of matters under investigation," a spokesperson said in a statement.
"We take seriously any suggestion that our staff have fallen short of the high standards of conduct expected of US government personnel."
The police said they were still investigating the incident.
Foreign diplomats in New Zealand are normally immune from criminal prosecution, under reciprocal international arrangements.
MFAT said it was clear with all diplomatic missions in New Zealand that it expected foreign diplomats to abide by New Zealand law, and to waive immunity should the ministry request it, if there are allegations of serious crimes.
A serious crime was considered to be an offence for which the penalty was a term of imprisonment of one year or more.
The ministry implemented the same policy for its own staff strictly, "but cannot compel other states to waive immunity", it said.