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

Seven-year-old Ancient King scored as the odds-on favourite in a hurdle race to complete a hat-trick over jumps.

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 flat races as well as over the jumps, has played a big part in the Weir achievements over recent seasons and guided Ancient King to victory, notching his 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."