Craig Williams has moved into a share of the lead in the Melbourne jockeys' premiership but his chances of a fifth title hinge on his international plans.

In the past few seasons, Williams has regularly taken up short-term riding stints in Japan during off-peak times in Australia, putting an end to any premiership hopes.

He says he has yet to decide whether that will be the case again this year at the back end of the Australian season.

The star hoop rode a winning double at Flemington on Saturday to take him to 24 city wins for the season, equal with reigning premier Damien Oliver.

Williams says if he decides against a Japanese stint then the premiership would be an aim.

"If I don't go to Japan it would be. I've got to work out if I go to Japan or whether I stay home," Williams said.

"Definitely everybody would love to be premiership-winning jockey. I've got four children and they are at the ages now where they follow the races.

"It might be something to strive for, for sure.

"If I go to Japan I can't win it. But if I don't go to Japan, of course it's definitely high on the radar and high on the priorities."

Williams won four-straight Melbourne premierships from 2005/06 to 2008/09, sharing the 2008/09 title with Oliver on 71 wins.

Oliver has won eight premierships and says he expects a tighter race than last season when he finished with an 18-win margin.

Williams and Oliver are two wins clear of Dwayne Dunn with Damian Lane and Regan Bayliss rounding out the top five with 20 wins apiece nearing the half-way mark of the season.