'Sickening' Drug Search And Privacy Screens At Sydney's Central Station

Police have defended a drug dog operation with "privacy screens" at a busy Sydney train station in the middle of the day, as a politician slammed it as "sickening".

Police sniffer dogs and "privacy screens" were deployed on platforms at Central Station, Sydney's largest, on Wednesday afternoon.

ABC employee Chris Dengate posted images on Twitter at 3pm showing dogs and screens set up near one of the main entrances to the station.

"The NSWPF regularly patrol our train stations and it is common practise to erect privacy screens for the purpose of a search. They are not strip searching tents," police told 10 daily in a statement.

An additional later statement added that Police Transport Command officers had "conducted an operation at Central Railway Station".

"These operations are conducted on a regular basis and often utilise privacy screens," the second statement said.

Police did not elaborate on what the outcome or results of the operation were. 10 daily has requested further information but has been told "at this stage no results are available".

NSW Greens MP David Shoebridge, who has long campaigned against drug detection dogs with his 'Sniff Off' campaign, slammed the police operation.

"Imagine being on your way home from work and being stopped by police with their drug dogs and strip searched in a tent on a station platform," Shoebridge said.

"This isn't some dystopian future, this is happening right now in Sydney. This is sickening."

READ MORE: Greens Take Police To Court Over Sniffer Dog Plan

READ MORE: New Police Sniffer Dog Policy At Music Events May Not Be Legal

The police operation caught the ire of many online.

Drug sniffer dogs have come under scrutiny in recent times with data showing the high rate of 'false positives' -- where a dog gives an indication that a person is carrying drugs, which turns out to be incorrect -- which can lead to invasive strip searches, being held up as evidence of unfair policy.

A 2011 study found this figure to be as high as 80 percent, with 11, 248 searches from a total of 14, 102 finding no drugs.

READ MORE: Drug Dogs Are Sniffing Out The Wrong Crims

A recent study from the University of NSW, based on data from the Bureau of Crime Statistics and Research, found that sniffer dogs are overwhelmingly nabbing young users of cannabis and ecstasy, rather than suppliers of harder and more dangerous drugs -- failing in their stated aim of addressing crime "relating to the supply of prohibited drugs or plants."

But those being caught for possession are being picked up with "the least harmful drugs," study author Dr Caitlin Hughes told 10 daily last month.

"It certainly very much calls into question whether drug dogs can achieve their aim, to target supply," she said.

"This is meant to target supply, but it's 18 times more likely someone will be picked up for possession. It's really not a very effective use of resources."