Tasmania's police union is pushing for lockout laws, similar to controversial laws operating in Sydney, to help deal with violence at Hobart's waterfront pubs and clubs.

Key points: The police union wants a trial of measures to restrict trading hours and access

The police union wants a trial of measures to restrict trading hours and access The union boss says some venues are a "breeding ground" for violence

The union boss says some venues are a "breeding ground" for violence Lockout laws operate in Sydney and Brisbane

The call comes after two men were viciously assaulted at the Observatory Bar about 4:50am on Sunday.

Two men were taken to hospital, with one needing treatment for a fractured eye socket and the other for a cut tongue.

The identity of the attackers is unknown.

The assault comes less than three weeks after respected University of Tasmania lecturer, Stewart Williams, died as a result of an alleged one-punch attack in Mobius, another waterfront venue which stays open until the early hours.

Stewart Williams died from injuries after an alleged one-punch attack at a waterfront nightclub. ( Supplied: University of Tasmania )

Police association president Colin Riley said his members who patrol the waterfront and deal with the victims of drunken violence wanted trading hours cut back.

"Why are licensing permits being allowed to operate to daylight hours?" he said.

"These licensed premises areas are a breeding ground and concentration for serious assaults and disturbances."

The union wants a range of measures trialled to combat what they see as a growing problem of violence around late-night venues.

Measures could include:

A cut-off time for the sale of "heavy" alcohol, possibly 11:00pm

A cut-off time for the sale of "heavy" alcohol, possibly 11:00pm Lockout laws restricting entry for new patrons, possibly from 1:00am

Lockout laws restricting entry for new patrons, possibly from 1:00am Closing times of 2:00am or 3:00am

"This staggered approach means rowdy crowds don't spill out into the street at one time, rather patrons gradually disperse," Mr Riley said.

Police resources being 'tied up'

Sydney's lockout laws introduced in February 2014 have been criticised, with some saying they are "killing the city".

Under the laws, patrons are locked out of venues from 1.30am, with last drinks served at 3:00am in Sydney's CBD entertainment precinct.

They were in response to the death of Daniel Christie as a result of a one-punch attack in Kings Cross the previous month.

Colin Riley says dealing with early morning waterfront violence is taking police away from other duties. ( ABC News: Jessica Hayes )

The laws, which had the backing of both Liberal and Labor parties, have also had vocal support from health workers and emergency services.

Similar laws are also in place in Brisbane.

The Tasmania Hospitality Association has previously said it was not in favour of the laws, and the Government has no plans to impose them.

"Liquor licensing permits are being approved by the Tasmanian Liquor and Gaming Commission, and yet police are the ones dealing with the associated problems," Mr Riley said.

"Why are police resources being tied up and dealing with these alcohol-fuelled problems when they could be tasked elsewhere and being more effective?

"Staff from the Tasmanian Liquor and Gaming Commission are not policing the permit at 4:00am.

"Allowing these poor permit decisions to continue is a waste of valuable police time, which could be better utilised proactively reducing criminal activity elsewhere in the broader community."

Council will look at issue 'more deeply'

Hobart Lord Mayor Anna Reynolds said the night-time economy was important for many cities, but that recent reports of violence were concerning and the council would be open to looking at the issue.

"Recently, council did extend a few licence operating hours … but I think we in some ways don't have a complete picture of what's happening down there when we have voted for extended operating hours," she said.

"The operators have told us everything is OK and we manage excessive drinking, but clearly there is a problem and we need to think about this a little more deeply as a council."

Some commenting on ABC Hobart's Facebook page supported the idea, while others said the solution was to enforce existing laws.

"How about using the existing Responsible Service of Alcohol laws more effectively? They don't get drunk without help," Jo Bain said.

"How about the security guard not let drunk people in and stop serving young people from 12:00am," Brett Ollington wrote.

Kylie Little posted: "Maybe just harsher penalties for those who do the wrong thing, instead of making the majority miss out due to someone else's mistakes."

An 18-year-old Moonah man has been charged with assault over Dr Williams's death.

Police are waiting on advice from the pathologist and Director of Public Prosecutions before deciding whether to upgrade the charge to manslaughter.