The 33-year-old Underbelly actor, who had been dating the actress for about a year before the incident two weekends ago, has now been dealt a restraining order from Taylor following "two unprovoked violent assaults".
A manager at the Westin Excelsior, where one of the incidents took place, confirmed to The Daily Telegraph that there was a "big noise". Taylor reportedly screamed for help after sustaining head injuries, apparently at the hands of Newton.
Police and an ambulance were called to the scene to calm Newton, but Taylor insisted that he was not under the influence of drugs or alcohol.
Newton, who has been dropped by his manager and will no longer present the Australian version of The X Factor, is believed to have re-entered a rehabilitation clinic.