A five-year study at Curtin University�s National Drug Research Institute found people were most likely to be involved in an assault between December 31 at 10pm and January 1 at 3.59am.
Alcohol Policy Research team leader Professor Tanya Chikritzhs said the sharp increase was likely due to the effects of alcohol on both perpetrators and victims.
�We know from studies that assaults that occur at night time � between 60 and 80 per cent� are likely to be alcohol-involved and New Year�s Eve is probably way up in the 90 (per cent),� she said.
�It�s the dark side of (New Year). These are assaults reported to police that range in seriousness, but it tends to be the more serious that are reported to police in the first place and many others don�t get reported. This is tip of the iceberg stuff.�
Prof Chikritzhs said the spike could come from pressure among friends to enjoy the celebrations and most assaults occurred in a domestic setting.
The confronting findings align with research by the Curtin-based National Alcohol Indicators Project, which associated violence to late-night alcohol trading. �There is no doubt late trading hours has a major influence on levels of violence,� she said.
�For assaults we found for an extra one or two hours open after midnight the risk of assault increases 70 per cent and there is a 49 per cent increase in drink-driver road crashes and that is a Perth study.
�When trading hours pulled back from a 6am close to a 3am close, venues found a 30 per cent reduction in violence that was ongoing.�
Prof Chikritzhs said the most effective way to control the problem was to change drinking behaviour or to impose stricter closing times at venues.