Drug detection dog opponents have cited fresh legal action after NSW Police followed through with a threat to deny entry to a Sydney music festival based on the canines' reactions.

At least two detection dogs were used to sweep crowds at the 'Above & Beyond' festival at Sydney Olympic Park on Saturday night.

The security operation drew criticism from civil libertarians after police declared they would deny entry if a detection dog produced a positive reaction, even if no drugs were found.

READ MORE Controversial sniffer dogs plan kicks in as festival-goers urged to report incidents

Volunteers from the "Sniff Off" campaign, which is backed by the NSW Greens, attempted to inform revellers of their rights using fliers outside the venue.

The group said it had spoken with ticket holders who were denied entry even though no drugs were found on them.

"This is a serious abuse of police powers," they posted on Facebook.

"We will see the NSW Police Force in court next week."

Officers had already ordered the volunteers to stop handing out fliers, citing a 2012 regulation which governs the entire Sydney Olympic Park precinct.

Activist Tom Raue, who was a plaintiff in an unsuccessful attempt to secure an injunction preventing the police plan, said the move from police was "disappointing".

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"We want people to be informed, clearly they don't," he said.

The group was then told members could speak with revellers but not hand out their pamphlets, which contained information about the detection dog program and advice to anyone pulled aside by police.

A NSW Supreme Court judge on Friday shut down the injunction attempt, saying the plaintiffs didn't have cause to complain about alleged injustices in advance.

The Greens say if police wanted revellers to be safe, they would instead advocate for pill testing and harm-minimisation approaches.

The party claims drug dogs can get it wrong up to 75 per cent of the time.

The plan also attracted criticism from the former commissioner of the Australian Border Force, Roman Quaedvlieg, who spent more than three decades in drug enforcement.

Mr Quaedvlieg 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."