Trainers have come forward to allege widespread use of performance-enhancing drugs within Australia's horse racing industry.

Thoroughbred horses are being injected with the same banned substances that were once used by US cyclist Lance Armstrong during his now discredited career, the trainers say.

Some high-profile trainers even describe drug cheating in the industry as rife, the Sunday Herald Sun reports.

"Trainers don't think they can compete unless they get an edge," one racing identity told the newspaper.

Another trainer said he could line-up blood-doping for $1400 per horse.

The alleged banned substances being used are EPO, a hormone that boosts red blood cell production and increases endurance, and opiate-based stimulants.

Trainers also claim the practice of "milk shaking" - or combining the drugs with sodium bicarbonate - is becoming common to mask the banned substances with officials failing to police cheating properly.

"They are terrified to get the big names," one trainer told the newspaper.

"But if this has been in bike racing for 25 years, how long has it been in horse racing?"

All trainers spoke to the paper anonymously, citing safety concerns.

But Racing Victoria and Harness Racing Victoria strongly deny drug problems in the industry.

"We have a robust and active testing regime in place for both EPO and opiate-based stimulants and there is no evidence to indicate the systematic use of either within the state of Victoria," Racing Victoria's integrity manager Dayle Brown told the paper.

The state government announced $4 million in funding last year to help the industry detect performance-enhancing drugs with more staff and upgraded laboratories.