Melbourne Cup-winning trainer Darren Weir has been charged by Victoria Police with animal cruelty, conspiracy and weapons offences.

Raids on the former horse trainer's Ballarat and Warrnambool properties in January allegedly uncovered a gun and conductive energy devices, known as jiggers, in his bedroom.

Weir, since banned by the racing authority, is one of four men charged over an investigation by sporting integrity intelligence officers and Racing Victoria.

He faces nine charges including conspiracy to defraud Racing Victoria stewards, possessing an unregistered gun and using a controlled weapon without an excuse.

The 49-year-old is also charged with multiple counts of engaging in torturing, abusing, overworking and terrifying a thoroughbred racehorse as well as causing unreasonable pain or suffering to a thoroughbred racehorse.

Fellow trainer Jarrod McLean, 38 from Yangery, is facing 16 charges including conduct that corrupts betting outcomes, animal cruelty and possessing cocaine.

Tyson Kermond, 27 from Warrnambool, is charged with six animal cruelty offences and one count of conspiracy to defraud Racing Victoria.

A 31-year-old Warrnambool man is charged with corrupt conduct.

All four are due to face Melbourne Magistrates court on October 23.

In a short statement, Racing Victoria confirmed it had been advised of the police charges.

"RV Stewards are giving these matters careful consideration and will provide a further update in due course," it said.

McLean's Yangery stables and former Weir employee Kermond were also targeted during the January raids.

In February, Weir was banned for four years by racing officials for possessing the jiggers.

The Racing Appeals and Disciplinary Board panel was told police and stewards found the shock devices in the master bedroom when they raided Weir's principal stables.

Weir trained a Commonwealth record number of winners last season from a stable described as an industry juggernaut.

It was a 100/1 chance that put him on the international map when Prince Of Penzance, ridden by Michelle Payne, won the 2015 Melbourne Cup.