NSW Police on Wednesday did not respond to questions about the efficacy of drug detection dogs, which has long been in question.

Statistics obtained from the state government show that, of searches conducted in 2011, a dog sat next to a person to indicate they might be carrying drugs in 14,102 cases. In 11,248 cases - approximately 80 per cent - no drugs were found.

Above and Beyond, an English electronic music trio, plays at the Sydney Showgrounds on Saturday night.

NSW Greens MP David Shoebridge, who runs the party's Sniff Off campaign, said the move was "a clear abuse of police powers".

“It’s not an offence to have a drug dog falsely indicate you are carrying drugs," he said on Wednesday morning.

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“We have known for many years that between two-thirds and three-quarters of drug dog indications are false positives where people are not found to be carrying any drugs.

“It’s hard to see how this kind of action by police could be legal, seeing how it involves punishment in the absence of any offence.

“The war on drugs is war on young people, with little to no impact on public safety or crime,” Mr Shoebridge said.

The move is in stark contrast to the ACT's Groovin The Moo festival, during which, in April, the nation's first pill-testing program was implemented.

More than 100 festivalgoers took part in the trial, with 85 samples tested. Half were found to be pure MDMA, while two samples were potentially deadly.