A bid to stop police from denying people entry to a Sydney music festival based on reactions from sniffer dogs has failed, with a NSW judge labelling it “a waste of everyone’s time”.

Two young partygoers had planned to launch action in the Supreme Court but were told on Friday their case was likely to be dismissed before an application for an injunction had even been filed.

The pair had hoped the challenge, backed by the NSW Greens, would be heard before Saturday’s Above & Beyond festival at Sydney Olympic Park.

It followed a threat by NSW Police on Facebook to “exclude any person from the venue that the drug dog indicates has or who has recently had drugs on them, regardless of whether drugs are located”.

Justice Michael Pembroke on Friday said the plaintiffs didn’t have cause to complain about alleged injustices in advance.

“We don’t waste our time with hypothetical issues like that,” he said.

NSW Greens MP Jenny Leong brushed off the defeat, insisting the police plan was an overreach of powers and claiming drug dogs get it wrong up to 75 per cent of the time.

“If the NSW Police wanted people to be safe at festivals they would be advocates of pill testing, they would be stopping the war on drugs and they would be supporting a harm-minimisation approach,” she said outside court.

Plaintiff Tom Raue agreed, calling for amnesty bins at concerts and regulation of the supply of party drugs.

“People have overdosed after seeing drug dogs approach them. They take a weekend’s worth of pills at once,” he said.

Mr Raue said punters singled out by sniffer dogs had been told to strip naked, lift up their breasts or scrotum, made to bend over and have a torch shone in their cavities.

“That’s a massive violation of your civil liberties,” he said.

Former commissioner of the Australian Border Force, Roman Quaedvlieg, who spent more than three decades in drug enforcement, dubbed the police move “extraordinary”.

“Festival drugs are risky granted but a person can have minute drug traces from handling cash, infused into garment fabric etc,” he posted on Twitter earlier this week.

“Using an ‘indication’, as they call it, to ban entry into a social event is too much.”

-AAP