Darren Weir has become the first trainer to prepare 400 winners in a season in Australia, bringing up the history-making milestone on his home track at Ballarat.

Seven-year-old Ancient King scored as the odds-on favourite in a hurdle race on Thursday, the gelding's third-consecutive win over jumps.

Last season Weir passed John Hawkes' previous record of 334 wins when he finished the 2015/16 season on 348.

This season's tally includes eight Group One wins and a record 120 Victorian metropolitan winners with six weeks remaining.

Irish jockey John Allen, who rides in both flat races and over the jumps, has been a part of the Weir team in recent seasons and guided Ancient King to his victory on Thursday which was the rider's 64th winner for the stable this season.

"Obviously it's been a great season and I'm sure it's a big team effort from all Darren's staff and everyone who is involved," Allen told broadcaster Racing.com.

"I suppose when I came out here at first I had never heard who Darren Weir was. But I'm sure everyone knows about him now.

"Look what he has done. He has been unbelievable and just gone from strength to strength."