Gary Moana Payne had been staying with his aunt in Sydney's eastern suburbs when he walked out of the front door one day with a mystery man.

That was 13 years ago. The New Zealand man has not been seen or heard from since that day.

Missing: Gary Moana Payne. Credit:NSW Police Media

After years of not knowing what happened to their loved one, Mr Payne's family are hoping a member of the public can shed some light on what happened after he left his aunt's house in Matraville in January 2001.

Mr Payne was 37 when he disappeared and, if he is still alive, would have turned 50 this year.