On New Year's Day the Emergency Department had a record 170 presentations, the previous record set in July last year at 169, and on Boxing Day 161 people went through the service in a 24-hour period.
Only 53 out of the 161 people presenting on the day needed to be admitted to hospital.
Dr Shaw said medical staff had been "absolutely fantastic" and worked longer hours and adjusted shifts to cope with the demand for services.
"I think it's just been one of those unpredictable and unexpected things. Our emergency department has been very busy, it hasn't let up yet. There have been a number of traumas and accidents, road traffic accidents, and there were some people injured at the speedway the other night."
It was important that people left the Emergency Department for emergencies only, he said.
"They should go to an urgent medical centre if they can do so, and from where they will always be referred to ED if they need that emergency care.
"But of course if people feel they have serious symptoms or are worried about having serious injury or illness then of course they should always call 111 and we won't turn anyone away."
Dr Shaw said the cost of seeking after hours medical attention couldn't be ruled out as a motivating factor for visiting the Emergency Department.
"It would be foolish to say that that couldn't be a factor, but of course for those people who are most vulnerable, children, infants and the elderly, there are subsidies and reduced costs available as I understand it.
"There will always be, I assume, a sector of people for whom money is tight and it's very difficult to afford things so I can understand that but it may not be the whole story for everyone."
Despite high demand, there was still 36 elective surgeries going ahead today and surgeries for all people needing cancer treatment, or who were at a high risk of deteriorating without an operation, would not be affected, he said.
A full list of GPs and after hours services for medical care can be found at www.ourhealthhb.nz.