Less than 24 hours after Peter Moody revealed he was under investigation for a positive test returned by one of his horses, fellow trainers Mark Kavanagh and Danny O'Brien finds themselves in a similar position.

A post-race sample taken from the Moody-trained Lidari after he ran second in the Turnbull Stakes in October was found to contain an elevated level of the cobalt.

In a statement on Tuesday morning, Kavanagh said one of his horses Moody has returned a positive swab in October but he did not name the horse or the substance.

"This morning Racing Victoria informed me that one of my runners tested positive to a banned substance in October last year," Kavanagh said.

"This has come as a complete shock to me as I have always placed great emphasis on integrity and operating within the Rules of Racing.

"We are, unfortunately, not the only stable in this situation.

"I am co-operating fully with the Racing Victoria Integrity Services Department to investigate how this could occur and hopefully we will resolve the matter as soon as possible."

Racing.com, the media arm of Racing Victoria, said O'Brien had also been issued with notification one of his horses had returned a positive test during the 2014 spring carnival.