Chase On The Case tested positive to arsenic after finishing third in a class 1 handicap.

Brown pleaded guilty to presenting the horse for a race when it wasn't free of all prohibited substances.

Chief steward Scott Quill said it was accepted that the swab finding was due to Chase On The Case chewing treated pine fencing.

"When assessing penalty, we also took into account that it was the trainer's first offence," Quill said.

Chase On The Case was disqualified from the race, with connections forfeiting $1700 in prizemoney.

The amended placings are: White Cliffs 1, Sh'bourne Rebel 2, Zagame 3.

Brown is a regular visitor to Tasmania and Chase On The Case won at Mowbray in February.

Mystic Journey is back in training as Spreyton trainer Adam Trinder ponders her likely spring campaign.

The star mare returned to work four weeks ago and Trinder reports she is in "good order."

"Our plan is to kick-off in the Bletchingly Stakes then go to the P B Lawrence Stakes," the trainer said.

"We had the same plan last year but ended up missing the Bletchingly due to a wet track."

Mystic Journey then won the P B Lawrence first-up.

This year's Bletchingly is over 1200m at Caulfield on July 25 with the P B Lawrence over 1400m at the same track three weeks later.

However Trinder said a proposal to reschedule some of the Melbourne spring races may alter his thinking.

"That would potentially be detrimental - we'd have to stall for a little bit," he said.

Mystic Journey will spend six weeks working at Trinder's farm before moving to his racing stables.