Australia's leading racehorse trainer Darren Weir is pleading for his career after being asked to show cause why he should not be suspended pending the outcome of an inquiry into electronic devices found in his stables.

Racing Victoria stewards charged Weir on Friday relating to possession of three of the taser-like devices known as jiggers.

They also charged him with failing to give evidence at the stewards inquiry and with conduct prejudicial to the image of racing.

RV opened the inquiry on Thursday, a day after they and Victoria Police officers from the sports integrity unit raided his stables at Warrnambool and Ballarat where they found the jiggers designed to give a horse an electric shock.

His assistant, licensed trainer Jarrod Weir who runs the Warrnambool stable, has also been charged with possession of a device and with failure to answer questions at the inquiry.

McLean has also been asked to show cause why he should not be stood down.

Stewards have scratched both trainers' horses from Moonee Valley on Friday night.

Weir's 11 horses scheduled to run at the Caulfield feature meeting on Saturday including the short-priced favourite, Nature Strip, in the W J Adams Stakes, have also all been scratched.

A third man, stable employee Tyson Kermond, has been charged with failure to give evidence at the inquiry.

A five-time Melbourne premiership winner, Weir runs the biggest stable in the country with more than 600 horses on the books and dozens of staff at both locations.

His biggest win so far came in the 2015 Melbourne Cup when 100-1 chance Prince Of Penzance claimed a famous victory for jockey Michelle Payne.

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