Drunk people who refuse police requests to move on will soon be made to sleep off their big night in sobering up centres being trialled by the state government.

The government promised to trial sobering up centres before it was elected and it has now announced it is setting up three.

Drunken and disorderly revellers in Kings Cross, The Rocks and George Street will be sent to sober up at the central police cell complex in Sydney's Central Business District.

Two other centres at Coogee and Wollongong will be set up in partnership with Non-Government organisations.

The Police Association has previously expressed concern about the plan, saying intoxicated prisoners are at greater risk of self harm and suicide.

But NSW Police Minister Mike Gallacher says police will only put people in the cells if they are conscious, not injured and not displaying violent behaviour.

Mr Gallacher says the trial will help combat drunken violence and sends a message that police requests should be obeyed.

"It's about saying to people 'when you speak to a police officer because of your drunk and disorderly behaviour, the words you utter to that police officer can determine where you spend the night," he said.

"In your own bed, or one supplied by me, and the one supplied by us isn't going to be very comfortable and isn't going to smell very good."

'O'Farrell's fight club'

The State Opposition says the centres are dangerous and should be abandoned.

Labor's police spokesman Nathan Rees says drunken fights are likely to break out in the cells.

"The idea that you pour half a dozen or more drunk young people into a cell for a night is a recipe for disaster," he said.

"This will end up as Barry O'Farrell's fight club."