Apprentice Beau Mertens celebrations of a winning treble at Caulfield have been curtailed with a 10 meeting suspension on two careless riding suspensions.

Mertens climbed to the top of the Melbourne premiership table going past Craig Williams with his three winners, but the double suspension was his third in the space of four days.

He was rubbed out at Sandown on Wednesday incurring an eight-meeting ban, while he received two 10-meeting ban following his winning ride on Onpicalo in the Ladbroke's Handicap.

He was outed for careless riding nearing the 1200m and again in the final 50m.

Racing Victoria stewards ruled his latest suspensions be served cumulatively and at the end his Sandown ban.

Mertens commences his suspension immediately and returns on May 28, but will miss only two city meetings as he chases the jockeys' premiership.

His treble on Shaf (Arvanitis Philanthropy Handicap), Pedrena (Pancare Foundation Plate) and Onpicalo took his season's total to 59, two clear of Williams.

Chief steward Terry Bailey they were seeing too much of the apprentice in the inquiry room.

"There's a lot of pressure on a young fella but you've got to get back to basics," Bailey said.

Mertens agreed saying his second suspension out of his winning ride on Onpicalo was a silly mistake where he allowed the horse to roll in nearing the finishing post.

"It was a silly mistake by me," Mertens said.

"I should have stopped and straightened him."

Mertens didn't ride his first city winner until April last year and spent last spring riding on the country circuit.

He said his early goal was to chase the apprentices' title but the senior premiership is something that is on his mind.

"I'm not going to go the early crow," he said.

"There's still a long way to go. I'm definitely not celebrating yet.

"The apprentice premiership was in my mind if it could be done and I thought it would be a great goal to kick over, but a bit more has come up lately."