The New Zealand government has helped trick officials on Nauru into letting one of their opposition MPs escape the country.

Internal Affairs Minister, Peter Dunne, says he took unique action to give the politician, Roland Kun, a New Zealand passport because the Nauru authorities had confiscated his local one.

A year ago Mr Kun was sitting on a plane in Nauru ready to head back to New Zealand when officials boarded it and escorted him off, cutting up his passport.

This left him stranded more than 4000 kilometres away from his Wellington-based home and family.

Mr Kun was allegedly kept on the island because he spoke out against corruption and human rights abuses in the Pacific nation.

Nauru authorities accused Mr Kun of being involved in anti-government protests outside parliament and being a threat to national security. He denies those claims.

"I knew the government was determined to keep me on Nauru away from my family, so I had to find a way of ensuring that I was able to travel without the government blocking my exit from Nauru," said Mr Kun.

Hon Peter Dunne came to his rescue providing him citizenship on humanitarian grounds, but was nervous this decision could hurt relations between Nauru and New Zealand.

Mr Kun escaped the day after elections took place saying he bought a ticket just an hour before the flight, and was so nervous he would be stopped before leaving.