Unusual demand at Christchurch ED - not a staff shortage - led to the plea for patients to seek non-urgent medical treatment elsewhere, Health New Zealand says.
In a post on its social media page on Monday, the hospital said its emergency department was "extremely busy" with "large numbers of people coming in for care".
It urged people who were severely unwell to go to the ED or call an ambulance, but asked that people with non-life-threatening emergencies go elsewhere "to reduce the pressure" on the department.
Everyone presenting at the department would be assessed for urgency, and patients with non-urgent conditions could expect an extended wait, it warned.
Health New Zealand Te Wai Pounamu deputy chief executive Martin Keogh said there had been an increase in surgical cases over the past three or four days, which had flowed on to the ED.
"Definitely not a staffing issue - this was purely demand, unusual demand, both for surgical care that puts pressure on our beds and our theatres and flows back into the ED at times."
The rise in surgical cases happened "from time to time" and the hospital tried to keep planned surgery going at the same time.
It was using facilities at Burwood Hospital to help out.
"We're always open ...we'll never turn anyone away, but obviously we have to triage the high acuity patients first."
On Monday it saw 76% of patients within the six hour target time.
"But we know some people waited a long time with low-acuity conditions."
Keogh said Christchurch Hospital's ED is the busiest in the country and there had been an 8% growth in patients over the past 12 months.
The biggest increase has been in the 0-14 and 24-40 age groups.
Keogh said they didn't yet know the reason for the demand increase but access to GPs, especially after hours, was a factor.
