Dunedin police are calling for action to prevent potentially deadly overcrowding at city bars.

Alcohol harm reduction officer Sergeant Ian Paulin said last week's district licensing committee hearing for Dunedin's Carousel bar highlighted the problems with the current system.

Carousel operator John Devereux admitted regularly breaching the second-storey bar's maximum occupancy of 50 people - in place because of risks of having only one exit - since the bar was established in 2006, but police did not find out about the limit until late last year.

Sgt Paulin said police did not know the occupancy limit of each of the city's bars and relied on what the duty manager told them at each visit.

''We haven't got the time to follow up on every licensed premises visit the troops do and find out if that number is accurate,'' Sgt Paulin said.

If bars were breaching their maximum occupancy, which was not always obvious, there was a chance of things going ''hugely'' wrong in the event of a fire or other disaster.

''There is massive potential for serious death and that has been well-documented overseas.''

This was why part of the police submission to Dunedin City Council's local alcohol policy (LAP) was for each bar to have to display its maximum occupancy next to the liquor licence.

The change would help both licence holders and enforcement agencies ensure bars were not overcrowded and had the potential to save a life.

Sgt Paulin was ''very'' hopeful it would be included in the LAP, which was to be voted on by the council soon.

At last week's hearing, Sgt Paulin said Southern District commander Superintendent Andrew Coster had called for an increased focus on overcrowding after being ''astounded'' after last year's All Blacks test match at the number of duty managers who had ''no idea'' of the maximum occupancy of their bars.