Kembla Grange trainer Paul Murray will front an inquiry into the presence of the banned substance cobalt in a vial of liquid found in his stable.

The Racing NSW Surveillance and Intelligence unit came across the substance during a routine inspection of Murray's stable on June 17.

Swabs taken from Murray's runners on that day have returned negative results but stewards have directed that stored samples of horses trained by Murray be resubmitted for further testing.

The inquiry will re-open when those results are known.

Newcastle trainer Darren Smith also faces an inquiry into the administration of cobalt and his horses have been transferred elsewhere after stewards barred nominations from the stable.

Racing NSW chief executive Peter V'Landys said the governing body would continue its vigilance in the search for illegal substances.

"Now that we have a test for cobalt and the fact that our new multi-million dollar state-of-the-art equipment can screen for a thousand prohibited substances at the one time (previously six), we will resubmit a number of samples for further testing," V'landys said.

"We have hundreds of stored samples and we will continue a program of retesting.

"Accordingly, we will continue to be relentless in our pursuit of persons obtaining an unfair advantage through the use of prohibited substances."

Cobalt occurs naturally in horses but research shows excessive levels to be both performance enhancing and detrimental to their health and well-being.