Ex-pat Australian Zac Purton has won the Hong Kong jockeys' championship, taking an unassailable four-win lead with three races remaining at the season finale.

Zac Purton has sealed the Hong Kong jockeys' championship, extending his lead to four over Joao Moreira with three races remaining.

Purton, who won the title in 2013/14, and three-time champion Moreira, have been locked in an enthralling battle over the last few weeks of the season.

The ex-pat Australian wrapped up the title with his win on Rise High at Sha Tin on Sunday for trainer Caspar Fownes to take an unassailable lead.

The final meeting of the Hong Kong season is also the last for Moreira who is to take up a contract in Japan.