Man 'betrayed' by brutal Mardi Gras arrest

A Sydney Gay and Lesbian Mardi Gras reveller has told a court he felt "betrayed" by police officers who punched his head into the pavement during an arrest in 2013.

Bryn Hutchinson was charged with assaulting and resisting an officer about an hour after the parade ended on March 2.

A judge later dismissed the charges and Mr Hutchinson is suing the force for assault, battery, false imprisonment and malicious prosecution.

The 37-year-old gave evidence at the civil trial in Sydney's Downing Centre District Court on Monday, claiming he was the victim of police brutality, which left him with bruises all over his body.

Mr Hutchinson said he'd had about six alcoholic drinks over several hours that night, and was feeling "cheery" as he made his way down to the Colombian Hotel in Darlinghurst with his partner, sister and a friend.

After failing to get into the busy bar, the man tried to cross Oxford Street when a policeman gave him a verbal warning against leaving the curb.

Security footage played in court showed other members of the public crossing as roadblocks had been removed, with street cleaning already underway.

But Mr Hutchinson said he was grabbed from behind and fell to the ground on his back before being flipped over and set upon by a group of police.

"I was kicked and punched several times," Mr Hutchinson said.

"There was marks on my face where I was punched into the tarmac."

The court heard that when he complained to an officer who was leaning on his back that he couldn't breathe the policeman told him "if you can talk you can breathe".

Mr Hutchinson became emotional when he said he was handcuffed, thrown into a police van and told he was being charged with assault.

"I was in the back of a paddy wagon crying and wondering what the hell had gone on," he said.

"I was screaming out that the cuffs were too tight. One of them yanked them further up my back ... my thumbs continued to be numb for several weeks after."

The gay rights activist said he'd previously had a good relationship with police at marriage equality rallies but added he's lost trust in them since the traumatic experience.

"I felt betrayed," Mr Hutchinson said.