A planned code of conduct would include a 3:00am lockout at licensed venues to help curb alcohol-related violence.

The draft code also proposes venues still open after 2:00am not serve alcohol shots.

After midnight, those venues would have to serve food and would be banned from serving drinks in most types of glass.

Premier Jay Weatherill said the late night trading liquor code of practice included more provision of such things as metal detectors and CCTV at venues and tougher controls on happy hours and other drinks promotions.

"There is no doubt that we need to lift the standards of late night venues to reduce the incidence of alcohol-fuelled violence," he said.

There have been deaths and serious injures related to alleged alcohol-fuelled violence in recent months.

SA Business Services and Consumers Minister John Rau said the laws would help venue operators.

"We don't want to see venues closing because patrons feel unsafe to go to the city," he said.

Feedback sought

Mr Rau said the Liquor and Gambling Commissioner would have the ability to grant exemptions or to crack down harder on venues doing the wrong thing.

The proposed code is now available for public comment until the end of next month.

The Opposition said it was not convinced of the merits of locking new patrons out of late-night venues after 3:00am.

Opposition Leader Isobel Redmond said the measures other than the lock-out generally sounded reasonable.

"We haven't been persuaded about the lock-out provisions simply because there's only seven premises in the state that we understand have 24-hour licences," she said.

"Most of those actually accommodate the people who, for instance, work at the Casino and go somewhere after work and there's no evidence to show those are the venues where there's been problems related to alcohol-fuelled violence."

Ian Horne from the Australian Hotels Association expressed concern the code would increase costs for businesses but not significantly reduce violence.

"There are some quite severe restrictions that potentially could cost lots of money," he said.

The father of a 24-year-old man allegedly assaulted outside a city nightclub said the planned new restrictions were a step in the right direction.

Doug Lindsley, whose son Jason was admitted to hospital after allegedly being punched outside the Zhivago nightclub in August, welcomed the proposed code.

"Would it have prevented the situation with my lad? I don't know. It may have, but at least things are going to be put in place so that changes can be made without actually going too far overboard to upset everyone's livelihoods and the likes," he said.