Last night the ABC's 7.30 reported the account of a Queensland man in his mid-20s who claimed he began a relationship with Mr Ashby when he was 15 years old. The man emailed Mr Slipper of their relationship after he saw media reports of Mr Ashby's sexual harassment case against the Speaker, who has stood aside while the matter is being investigated by the courts.

In emails sent to Mr Slipper and obtained by the ABC, the young man said he and Mr Ashby met when the former aide moved to Townsville in 2003.

Mr Slipper forwarded the emails to the police on June 16, saying: ''Although the allegations that have come to light predate Mr Ashby's employment with my office, they raise issues of possible criminal conduct. In these circumstances, I cannot ignore the allegations.''

The ABC reported that police were in the preliminary stages of investigating the matter.

One email read: ''In 2003 I met James Ashby through a mutual friend. He was working for a radio station and in the process of moving to Townsville we began a sexual relationship for a few weeks before James broke it off as he had started a relationship with another person which lasted two or three years.''

''I was 15 at the time, however what we did under Queensland law cannot be consented to under the age of 18,'' he wrote.

''The guy James broke it off for was also 15 at the time they began their relationship.

''James left me feeling used and disgusted with myself.''

The ABC also reported seeing Facebook messages, sent by Mr Ashby to the young man, which continued as he prepared to work for Mr Slipper.

''I really never gave an explanation behind me f---ing off and not saying why. Strangely enough the reason was so pathetic that I thought I'd share it with you. Your mum freaked me out when she walked in on you and me in bed. That did my head in for some strange reason,'' he wrote.

Mr Ashby's spokesman declined to comment last night. Mr Ashby is suing Mr Slipper and the Commonwealth, claiming Mr Slipper made unwelcome sexual advances between January and March this year.

But Mr Slipper claims Mr Ashby ''carefully cultivated'' a relationship of trust and confidence with the Speaker from mid-2011 and ''gradually introduced into his exchanges … occasional ribald language and sexual innuendo'' after he began working in Mr Slipper's office last December.

Mr Slipper defected from the Liberal Party to become parliamentary Speaker last year and stood aside in April after Mr Ashby lodged the sexual harassment charges against him.

The former Howard government minister Mal Brough won Liberal National Party preselection for Mr Slipper's Sunshine Coast seat of Fisher on Sunday amid controversy about his role in the sexual harassment case.

Mr Brough allegedly had extensive contact with Mr Ashby before he brought the case against Mr Slipper.

Mr Brough spent much of yesterday defending his role in helping formulate the case of sexual harassment and Cabcharge rorting lodged against Mr Slipper by Mr Ashby.