The state's top crime statistician says there is no basis for claims that lockout laws are working, arguing that it will take at least until Christmas before enough data is available to conduct a proper analysis.

Don Weatherburn, director of the NSW Bureau of Crime Statistics and Research, said there is no evidence the laws introduced by the NSW government in February have had any effect on levels of non-domestic violence in Kings Cross and the Sydney CBD.

BOCSAR director Don Weatherburn has called for a re-think on the approach to crime and imprisonment. Credit:Quentin Jones

Dr Weatherburn said two factors need to be taken into account: that there was "very little data after the lockout laws to make any judgement whatsoever" and that the numbers "bounce around quite a bit".

The downward trend of violence in the Sydney CBD and Kings Cross "began well before the lockout laws took place," he said.