People who are intoxicated and disorderly on Sydney's streets this weekend could find themselves locked in a sobering-up centre.

The New South Wales Government is starting its trial of the centres in Sydney's CBD and the eastern suburbs.

The mandatory centre in the CBD will be set up in police cells and run by officers, while another in Coogee will be operated by a non-government agency.

It coincides with the British and Irish Lions rugby decider against the Wallabies, with police able to take drunk people to the centres if they refuse to go home.

Police Minister Mike Gallacher says those who end up in the centre will also get a fine.

"So if you're a frequent flyer, very shortly you are going to work out that it was much cheaper for you to have simply obeyed the direction and stay in your own bed rather than the one at the Sydney courts," he said.

However, Opposition health spokesman Andrew McDonald says sobering-up centres are inherently dangerous.

"You cannot tell if somebody has had too much to drink, too much of a dangerous drug or has a head injury or diabetes," he said.

"The reason that these drunk tanks were abolished in the first place was because people used to die in police cells when they were not being observed."

An alliance of emergency service workers has echoed the concerns.

Last Drinks Coalition spokesman and Midwives Association secretary Brett Holmes says it is a haphazard approach that will put safety at risk.

"Police will be faced with making a complex medical diagnosis they're not trained to conduct, on the streets," he said in a statement.

"There's no clarity around how the nursing staff will be protected or what the ratio of nurses to patients will be."

Mr Holmes says the Government needs to deal with the real issue of alcohol abuse.

The Government says it will open a third sobering-up centre in Wollongong by the end of the year.