Police are warning the public about a high risk sex offender now residing in Vancouver.

Matthew Ralf Harks is a 28-year-old white male who has a history of sex-related crimes involving children. He is 5-8 tall, has blonde hair, blue eyes and weighs 146 lbs.

Police believe there is a high risk that he will commit further sexual offences against children.

"We believe that he poses a significant risk to the safety of female children," Const. Lindsey Houghton said at a press conference on Monday.

Harks was convicted of sexual assault in 2007 and served a three-year sentence.

He also has two previous convictions for sexual assault, in addition to another conviction for failing to abide by his probation order.

Harks is not allowed to have contact with children under 16 or to possess pornography.

He is banned for life from visiting any place where children are known to gather, from using computers to communicate with children under 16, and from seeking any employment or volunteer position of authority over children under 16.

"We're asking anyone who witnesses Mr. Harks in their community breaching any of these conditions to phone their local police immediately," said Houghton.