A major new study is being launched into the effect of controversial lockout and last drinks laws in Kings Cross and the Sydney CBD, including whether they have pushed violence to neighbouring areas.

The revelation comes just a day after allegations that The Star casino at Pyrmont, which sits outside the lockout zone and is therefore exempt from the restrictions, is under-reporting the number of assaults at the venue.

The director of the NSW Bureau of Crime Statistics and Research, Don Weatherburn, revealed the new analysis to Fairfax Media, which was underway before the allegations against the casino surfaced.

Dr Weatherburn said the public debate around the 1.30am lockout and 3am last drinks laws has proceeded with the understanding that reviewing them once was sufficient.