NSW violence reforms haven't delivered

New laws designed to increase conviction and guilty plea rates in NSW domestic violence cases has had little to no effect.

The NSW Bureau of Crime Statistics and Research has found the reforms introduced in 2015 - which included police being able to introduce recorded video or audio evidence against an alleged offender into legal proceedings - hasn't worked.

Its comparison of court outcomes for cases with and without this evidence show its presence had either no effect - or just a small one - on the probability of conviction.

BOSCAR executive director Dr Don Weatherburn noted the reforms were also designed to reduce the trauma for complainants, who had to recount events in front of alleged offenders.

"They may have achieved this objective, even if they had no material effect on the DV (domestic violence) convictions or plea rates," he said on Thursday.