Following allegations of police brutality at last month’s Sydney Mardi Gras, a man claims he was ordered to strip naked during a drug search in full view of bystanders.

Gray Leeson, from Sydney, said to news.com.au that he was left “humiliated” and “bullied” when police ordered him to remove his trousers and underpants as part of the search.

The 55-year-old was picking up tickets for the gay festival when the incident happened.

Mr Leeson was approached by a sniffer dog at 4.30pm on Saturday 23 February, at the gates of the Sydney Mardi Gras Harbour Party in the Botanic Gardens, and taken by police into a covered enclosure for a full search.

He said he was patted down and repeatedly told he was lying when he said he did not possess any drugs. Then he claims police said: “Now drop your pants.”

He alleges there was a gap in the tarpaulin covering the area and people walking past could see inside. “[They could see] my bare butt,” he told news.com.au. “I was not comfortable with that at all.

“It’s a complete abuse of their power … I feel embarrassed and humiliated.”

A New South Wales Police spokesperson refused to comment on the allegations.

The force has confirmed it has now launched an investigation into the conduct of its officers – the third internal inquiry since video footage emerged of alleged police violence at the event.

In one incident an officer is allegedly seen grabbing a 32-year-old man by the throat.

A gay rights campaigner also claimed that in a separate incident, he was subjected to police brutality.