A number of items, including a gun and what is thought to be a Taser, have also been seized.

Uniformed and plain-clothed officers swooped on stables owned by Weir at Miners Rest and in Warrnambool early on Wednesday morning.

Weir, 48, from Miners Rest, a 38-year-old Yangery man and a 26-year-old Warrnambool man were arrested, and a number of items - including a firearm and a conducted energy device - were seized.

Detectives from Victoria Police's Sporting Integrity Intelligence Unit will now interview the three men.

Racing Victoria's executive general manager of the integrity unit, Jamie Stier, confirmed three people had been arrested as they investigated potential offences against the rules of racing.

“Racing Victoria’s Integrity Services team has been conducting an investigation into the activities of licensed persons in the Warrnambool and Ballarat areas," he said.

"During the course of our investigation we sought the support of Victoria Police’s Sporting Integrity Intelligence Unit on the matter, instigating their investigation.

“The Sporting Integrity Intelligence Unit this morning executed warrants at properties in Warrnambool and Ballarat where they arrested three licensed persons for questioning."

A Victoria Police spokeswoman said the trio would be interviewed in relation to sporting integrity matters, including obtaining financial advantage by deception, engaging in conduct that corrupts or would corrupt a betting outcome of an event or event contingency, use of corrupt conduct information for betting purposes, and attempting to commit an indictable offence namely obtain financial advantage by deception.

The raids are part of a continuing investigation. No charges have been laid. There is no suggestion the allegations are true, only that they are being investigated.

Due to the ongoing investigation, he would not comment on the identities of those arrested or the details of the investigation.

At about 6am, Racing Victoria compliance team officials and Victoria Police sports integrity unit officers took part in the searches.

It is understood some vehicles and cars were also examined at Warrnambool and Ballarat.

There have been persistent rumours during the past two months of a significant investigation.

The RSPCA said it was unaware of any investigation when contacted by The Warrnambool Standard in the past two weeks.

RSN Racing & Sport radio reports federal police visited Weir’s Ballarat stables some weeks ago where they may have seized an item central to an on-going inquiry.

Weir has five runners due to race at Mornington on Wednesday.

He was in New Zealand at the Karaka Sales on Sunday.

Weir, 48, has been training horses since 1995, recently taking out the Melbourne Cup with Prince of Penzance in 2015.

He is currently the most successful trainer in the national trainer's premiership, and counts hundreds of horses as part of his stable.

Born in Berriwillock, a small Mallee District town in Victoria, Mr Weir left school at age 15 to work under experienced trainers.

He moved to Ballarat in 2001 and later acquired stables at Warrnambool to compliment his Ballarat base.

Weir holds the Commonwealth training record for most number of wins in a season, first breaking it in season 2015/16 with 348 wins, and eclipsing it again each year since.

Racing Victoria has released the following statement, attributed to executive general manager of integrity Jamie Stier:

“Racing Victoria’s Integrity Services team has been conducting an investigation into the activities of licensed persons in the Warrnambool and Ballarat areas. During the course of our investigation we sought the support of Victoria Police’s Sporting Integrity Intelligence Unit on the matter, instigating their investigation.

“The Sporting Integrity Intelligence Unit this morning executed warrants at properties in Warrnambool and Ballarat where they arrested three licensed persons for questioning. Members of the Racing Victoria Integrity Services team attended licensed stables to assist Victoria Police and to investigate potential offences against the Rules of Racing.

“As the matters are the subject of on-going investigations by Victoria Police and Racing Victoria we are not at liberty at this time to disclose the identities of the persons arrested nor the details of the investigations.

“Racing Victoria is committed to maintaining the highest integrity standards in our sport and, where appropriate, we will continue to work with Victoria Police on those investigations.”

Weir has been based in Ballarat for the past 15 years.

He won the $350,000 Ballarat Cup this year with Kiwia, and had previously won it in 2004 with Just The Part.

He had recently broken his own record for the greatest number of winners trained in a year.

The raids follow the impostion of a $90,000 fine to go with the 2018 life disqualification for another Ballarat trainer, Robert Smerdon, over the trainer's role in the Aquanita case.

Racing Victoria had sought a maximum $100,000 fine in submissions to the RAD Board before penalties were handed down on May 10, 2018.

Smerdon, along with Greg and Denise Nelligan, were handed life disqualifications following an investigation into the Aquanita race day treatments case.

Others banned were trainers Stuart Webb for four years, Tony Vasil for three years, Trent Pennuto for two years, Liam Birchley for one year and stablehand Daniel Garland for one year.

Ballarat Courier