Dr Sage said some aggressive patients had been "marched out'' by hospital security but police had not been called and no staff had been physically assaulted.
He had rostered a fourth doctor on for New Year's Eve - the busiest night of the year.
Staff were also expecting an influx on January 1, as revellers sobered up and realised they were injured.
He said overcrowding would be an issue and there was a possibility that if the Emergency Department became "jammed up'', patients would be treated in a hospital ward.
"I would say that we could anticipate waiting anywhere between 4.5 to eight hours. Obviously, very sick people get seen sooner,'' he said.
Dr Sage said staff were also treating some minor ailments because people were saying they could not get in to see their doctor during the holidays.
However, some did little to help themselves, like washing wounds or taking pain killers before arriving at ED.
"They haven't even done the basics for themselves. There's a degree of helplessness about some people that turn up,'' he said.
Officials at Hawke's Bay Hospital said they too were seeing too many people going to the emergency department with minor complaints.
"Unless it is an emergency, people should go to one of the accident and medical centres open in Hastings and Napier over the holiday period,'' said chief operating officer Warrick Frater.
Hospital staff had been busy in the festive season, with 150 patients visiting the emergency department on Boxing Day and more than 130 on most other days during the holidays. The normal daily figure is 100-110 patients.