Aggressive behaviour has increased outside Sydney bars but the number of alcohol-related injuries at St Vincent's has declined since the city's 1.30am lockout was introduced, according to submissions made to a parliamentary inquiry.

Jeremy Fraser, general manager of Side Bar in the CBD, told the inquiry he has seen "a marked increase in violence around my venue, usually directed towards myself or security staff".

Aggressive behaviour has increased outside Sydney bars since the introduction of the lockout. Credit:Daniel Shaw

"Since the introduction of the lockout laws, our need to call police for assistance has increased from about once a month, to almost weekly. This is directly due to the lockout laws," he wrote.

"Every night we are in conflict with at least 8-20 guests, who all feel they are being unfairly refused. We explain the laws in detail, however this has little effect, and regularly turns to conflict, sometimes physical."