How many patients are affected is unclear, but the Southern District Health Board has shelved all deferrable elective surgery before Christmas.
Bed access issues had led to full emergency departments, particularly in Southland, and put enormous pressure on the system and staff, SDHB chief medical officer Nigel Millar said.
Doctors were trying to make as many hospital beds available for people arriving very unwell at ED, although the reason for the sudden surge in cases was unclear.
"More patients seem to be presenting acutely unwell, and with complex needs," he said.
"It’s not clear if this is still a carry-over from care that was delayed due to the Covid-19 lockdown, or if there are other factors involved."
Dr Millar said that anyone who needed emergency care would receive it, and that by the time most patients reached ED it was the appropriate place for them to be.
"This has been a really challenging year, and it’s not over.
"Again we thank everyone for their understanding as we do what needs to be done for our community."
Dr Millar said it was unfortunate long-awaited procedures had been deferred for so many people, but he hoped they understood it was because the DHB had had to prioritise the region’s most unwell people.
"We also appreciate the general practitioners, home and community support workers, and many others, who are supporting people while they await the surgeries and interventions they need."
A report to be considered by the SDHB’s hospital advisory committee next week said the increase in demand at EDs was a national phenomenon.
"Other DHBs are also reporting higher length of stay and that this is putting pressure on both elective surgical delivery and beds in hospitals," specialist services executive director Patrick Ng said.
"Anecdotally, an issue that has been identified by others is access to aged residential care beds, but this needs to be validated and quantified."
A group had been formed from throughout the local health system to analyse what was causing the issue.
"We look forward to understanding the challenges better," he said.
