AN investigation into claims on-air presenters accepted "free shares" in racehorses is being conducted by racing broadcaster TVN.

MARK DUNN reports in the HERALD SUN that the internal investigation, dubbed by racing insiders as "shares for comment", was launched after allegations were raised about whether the part-ownership, if offered for free, breached laws requiring stakeholders have equity in the thoroughbreds.

The Victorian and NSW race broadcaster TVN is understood to be looking at the racehorse shares of at least two, and possibly three, presenters and whether money changed hands.

About two weeks ago a presenter correctly declared ownership in one runner.

Such declarations occur periodically during coverage and there are no prohibitions on media commentators or presenters owning part or full shares in horses.

But questions surround whether the shares breach Corporations Act equity rules requiring that each shareholder pay the same amount to obtain individual shares.

One of TVN's advertisers, Dynamic Syndications, said in a statement it "wishes to go on public record" to refute any assumption horses it handled were involved.

Dynamic Syndications director Dean Watt told the Herald Sun his company spent "hundreds of thousands a year" in advertising on TVN.

He said "if I see someone get a free kick" out of promoting a horse or stable, "I'm not going to be happy about it".

An industry source said many media personnel within racing, whether at TVN, Sky or free-to-air networks, had shares in horses.

"We encourage our guys to participate in the industry," he said.

But TVN declined to "confirm or deny" whether it had launched an internal investigation into whether "free" shares had been offered to any presenters.

"We can't really at this point discuss the matter, it's not appropriate," TVN spokesman Stephen Dole said.

He described any review as a "human resources" matter and therefore the network was prohibited from discussing the issue publicly.