More than nine times as many violent offences are committed in the New Year's Eve window between 9pm and 3am than at other times over the festive period.

With Sydney's hospital emergency departments bracing for a flood of patients on New Year's Eve, crime statistics show an average of 312 assaults recorded in that six-hour window, with the night the year's worst for violence.

"You can have lives destroyed": Dr Tony Grabs. Credit:Steven Siewert

Over the past five years, 125 violent offences on average were committed in the final three hours of New Year's Eve, soaring to an average of 433 in the first three hours of New Year's Day, an analysis of NSW Police records by the NSW Bureau of Crime Statistics and Research found.

It is a similar story in Victoria, where significantly more assaults and sexual assaults occur in the week leading up to New Year.