The federal government says it was not involved in a decision to deny a team of UN investigators access to Australian detention facilities on Nauru.

Human rights advocates said it was the second time in a month that UN delegates have been refused access to Australian detention centres offshore.

Inspectors from the UN Working Group on Arbitrary Detention had just completed a tour of New Zealand and were due to fly out to Nauru when the visit was cancelled, according to reports in New Zealand media.

The group’s leader Mads Andenas said the Nauruan government had cited “practical reasons for it not being suitable or practical for us to come."

A spokesman for the Nauruan government told ABC on Wednesday the claims were a “publicity stunt” and that the investigators had not been invited to visit the island nation.