Attorney-General Simon Corbell said the government's long-awaited response to anti-social and violent behaviour in entertainment precincts was due in a fortnight. His comments came a day after police released graphic images of another one-punch assault outside a Canberra nightspot.

On Friday police said they were searching for a man who punched another man to the ground outside the PJ O'Reilly's pub in Greenway about 3am on Saturday, December 12.. Security footage showed the victim backing away from an argument, as a third man hit the victim in side of the head.

Another man is seen to rush to his aid as he lies on the footpath. He was later taken to hospital by ambulance crews.

Mr Corbell praised police for their response to "a shocking and reprehensible incident".

"The government's position is we have to tackle the causes of alcohol-fuelled violence at its source," he said.

"That means the supply of alcohol and how it is provided so that people drink responsibly, and don't lead to alcohol-fuelled violence."

He said existing liquor licensing laws already included provisions for lock-out laws, but the government had not yet decided to implement them. Popular entertainment precincts in Sydney and Melbourne have seen new laws restricting entry after designated times.

Mr Corbell said increases in the number of police in the past four years had helped, but alcohol service and crowd control were central to fixing problems stemming from anti-social behaviour.

"We will be looking at a broad range of measures, but clearly service of alcohol and the times of that service and other approaches like that are very high on the agenda.

"There's no doubt that as a culture, as a society, we have a particular view of alcohol and it's not always a healthy one but that's where the law can play a very important role."

A police spokeswoman told Fairfax Media they chose to release the security footage this week after pursuing other lines of inquiry in the six weeks since the assault. News of the attack came after another alleged "coward punch" in Civic after Canberra's New Year's Eve celebrations.

A Canberra man had emergency surgery to his jaw following the alleged assault outside the East Row Supa 24 convenience store in Civic, shortly before 3am on New Year's Day. A 20-year-old man has been charged over the assault.

"This type of senseless violence can have tragic consequences; we know that just one punch can kill," a police spokesperson said.

"This is a cowardly act which will not be tolerated."

The attacker is described as being between 175 and 183 centimetres tall, with light complexion and brown hair. He was wearing a white T-shirt and black or blue pants at the time of the assault.

Police are urging anyone shown in this video to come forward.

The attack sparked debate about the penalties levied at the perpetrators of one-punch assaults in the ACT. Mr Corbell previously said there was no evidence suggesting that laws such as minimum mandatory penalties have any value as a deterrent.

Public Health Association of Australia chief executive Michael Moore called for sensible alcohol policies to replace "lax" laws in order to take pressure off public hospitals.

"Emergency department visits are at a high with 15 per cent of patients there due to alcohol-related injuries," he said.

"These resources could be better utilised to treat non-alcohol related patients. During peak alcohol usage days including Australia Day, our emergency departments get inundated with intoxicated people, placing a huge burden on hospitals.

"Intoxicated people are causing harm to themselves and others creating a dangerous environment."

Witnesses or anyone who can identify the attacker should contact Crime Stoppers on 1800 333 000, or via act.crimestoppers.com.au.