Racing Victoria now has the power to warn off unlicensed persons under changes to state legislation.

The changes to the Racing Act 1958 provides Racing Victoria with jurisdiction over unlicensed persons participating in the racing industry including commission agents, punters and veterinarians.

It also gives racing integrity commissioner Sal Perna the power to compel witnesses to attend inquiries.

"It is only fair that persons who are engaged in racing and deriving an income from the sport should be required to abide by the Rules of Racing, whether they are licensed or not," Racing Victoria's chief steward Terry Bailey said.

"From today we now have the authority to request unlicensed persons to attend inquiries and penalise them accordingly for breaches of the Rules of Racing which is a must if we're to uphold the integrity of the sport."

The push to change the legislation was prompted by the Victorian Civil and Administrative Tribunal ruling in a 2010 case involving commission agent Neville Clements.

VCAT ruled Racing Victoria did not have jurisdiction over unlicensed persons.