A group of six Australian men allegedly threw matches in online game Counter-Strike: Global Offensive and then bet on the fixed results.

Victoria Police raided three homes in outer Melbourne suburbs on Wednesday and two more homes on Friday, arresting six men aged 19 to 22.

The investigation began in March after police received information from a betting agency about suspicious activity linked to a Counter-Strike: Global Offensive tournament.

"It's alleged that players were arranging to throw matches and subsequently placing bets on those matches," Victoria Police said in a statement on Friday.

"It's believed at least five matches were impacted and over 20 bets were put on the matches by Australian punters."

In game footage of Counter Strike: Global Offensive. (Supplied)

All six were interviewed and released pending further inquiries.

The charge of engaging in conduct that corrupts or would corrupt a betting outcome or event carries a punishment of up to 10 years' imprisonment.

Counter-Strike: Global Offensive is a first-person shooting game in which players team up as terrorists or counter-terrorists and work together to eliminate each other.

Assistant Commissioner Neil Paterson said this investigation involving the esports industry was one of the first of its kind by Victoria Police.

"Esports is really an emerging sporting industry and with that will come the demand for betting availability on the outcomes of tournaments and matches," he said.

"These warrants also highlight that police will take any reports of suspicious or criminal activity within esports seriously, and we encourage anyone with information to come forward."