Former New South Wales assistant police commissioner Clive Small has revealed he warned the State Government about problems in Redfern just three months before a violent riot erupted last month.

In an ABC TV Four Corners program to be aired tonight, Mr Small says many of the problems affecting the Redfern area stem from police inability to curb heroin use in the area.

Mr Small says the anti-drug plan for Redfern, introduced by the New South Wales Government more than a year ago, is failing.

He says the rising use of heroin in the area contributed to the violent riot there last month.

NSW assistant commissioner Bob Waites admits police morale has been affected by the inability to enforce the drug laws in Redfern.

Mr Small has told Four Corners about the response when he warned about the growing unease in Redfern.

"What we were told was that there were adequate police to deal with the problems in Redfern, so that was the sum total of the feedback," Mr Small said.

"I thought it was an interesting response and a brave response - I thought it was highly inaccurate."Four Corners also says three people have given statements suggesting police were chasing Redfern teenager Thomas Hickey shortly before the accident that caused his death.

The 17-year-old's death sparked violent rioting in Redfern last month but police have consistently denied chasing him and say they are not responsible for his death.

One man has told Four Corners he saw a police paddy wagon travelling about three car lengths behind Thomas Hickey before he rode through a gate on his pushbike.

Another witness, Stewart Clanachan told the program he saw a police paddy wagon near where he last saw Thomas Hickey riding before his accident.

"As we looked to the right, I happened to see there was a paddy wagon there, just straight up against the gate," Mr Clanachan said.

"What happened was - it's only a pathway and there's enough room for pedestrians or a guy on a pushbike to get through, and the paddy wagon was just stopped at the gate."

'Crimes unreported'

Four Corners has also been told by members of the Aboriginal community, including Thomas Hickey's mother, Gail Hickey, that girls are not reporting the crimes because they are scared of their attackers.

"People have been raped down there, but they won't tell no one - why's that?" Ms Hickey said.

"Because they're frightened of the people that done it to them."

Gail Cargill has told the program she tries to avoid Redfern because of the violence and drug problems.

Ms Cargill says her niece was sexually assaulted and went to police, but many such crimes go unreported.

"She was bashed and raped and the person that's supposed to be responsible was arrested but let out on bail," Ms Cargill said.

"I really don't know people over there at the moment because I don't go there, but she was one them.

"But I've been told by many people that there's been a lot of young girls that've been sexually assaulted there."

Ms Cargill is one of those charged by police over the riot.