A former South African man convicted of child molestation and awaiting sentence appears to have skipped the country on a fake passport, leaving his wife to take the rap.

Hamilton police have contacted Interpol to try and track down Christopher Ian Crause, 47, who should have been sentenced last month, but failed to turn up to court.

In March, Crause was found guilty of four counts of sexual connection with an underage girl, four of doing indecent acts with an underage girl and two of supplying cannabis to a person under 18, the Waikato Times reports.

Police believe Crause left the country on a fake New Zealand passport in the name of Daniel Finnerty. They have charged his wife, Brigitte Daniele Crause, 51, with helping him get it.

The couple came to New Zealand in 1997.

Despite being convicted, Crause and his family flew to Brisbane in May, but Crause did not return.

An angry Brigitte Crause told the newspaper they had "a bit of an argument" and he disappeared. He may have been staying with relatives in Australia, she said.

Crause's offending started in 2009, when he and his wife used a dating website to look for swingers who wanted to meet up for sex.

They met one couple and Crause was introduced to their 15-year-old daughter and her 14-year-old friend.