A record number of people were seen at Hawke's Bay Hospital's Emergency Department on Monday last week.
The hospital saw 188 presentations to its ED over 24 hours, forcing some planned care operations to be postponed.
Chief medical and dental officer Robin Whyman said the hospital was experiencing very high demand with the majority of presentations being serious medical conditions that needed hospital admission and care – most of the patients were aged over 50.
Emergency Department head Mark Barlow said the unprecedented demand may be a predictor for the coming winter months and urged people to be proactive about their health.
"With winter approaching we want people to think about their health and to take steps to get medical attention if they began to feel unwell," he said.
"When we have this kind of demand on our services it's very tough on our staff, who are working under enormous pressure, and at the same time our patients with more minor illnesses and injuries have to wait longer than they should to be seen," Barlow said.
Whyman said the clinical teams were working together to improve the flow through the hospital to relieve some pressure on ED.
A Hawke's Bay District Health Board spokeswoman said Mondays are traditionally busy at the hospital.
"The building is designed in terms of space for about 75 patients a day, but is staffed to cope with about 130 presentations a day," she said.
The spokeswoman added when presentation numbers increase more staff are called on to assist or stay longer.
Healthcare colleagues in urgent care facilities in the community had also experienced a surge in demand over the past weekend and Monday, according to Whyman.
The volume of admissions meant some planned elective operations were postponed on Tuesday as the hospital was at capacity - those affected have been contacted by the hospital.
Whyman added people with chronic illnesses need to regularly check in with their GP and seek help immediately if they noticed any changes in their medical condition so they don't need an emergency hospital admission.