Ambulance Victoria activated another code red in the early hours of Saturday morning as extreme demand put paramedics under pressure.
A surge in calls just before midnight in Metropolitan Melbourne forced Ambulance Victoria to escalate its response plan for several hours.
Ambulance Victoria called in off-duty staff, used non-emergency ambulances to respond to emergencies, and undertook rapid offloading of patients at hospitals.
The situation returned to normal about 3am.
Ambulance Victoria said it had about 140 staff furloughed due to COVID-19, which had increased from about 30 at the start of October.
Victoria's health department on Friday reported 54 deaths from COVID-19 over the previous week, and 26,971 new cases of the virus.
There are 550 people in hospital with COVID-19, of whom 21 are in intensive care.
Michael Georgiou from Ambulance Victoria said a code red had been called eight times in 2022, and a code orange had been called 17 times in the month of November alone.
"We are seeing an increase. Last month we had our highest number of lights and sirens code one cases in history and so we are seeing demand increase," he said.
"I think we did about 1,250 cases yesterday which is well and truly above our demand and we've seen our highest demand on record for November."
Victorian Ambulance Union secretary Danny Hill said the system had been under strain for some time and paramedics were exhausted.
"Literally just back-to-back cases, never getting a break, always working overtime at the end of their shift," he said.
"They've escalated to code orange almost every night over the past several weeks and it's happening in conjunction with the Omicron wave that we're seeing which is causing major strain on the hospitals."
Mr Hill said many call-outs were from people who could have contacted GPs, pharmacists or health advice lines rather than paramedics.
"The vast majority of the cases they're attending to and being sent to are patients that don't need any form of paramedic care," he said.
The union said low morale and poor working conditions were leading many Victorian paramedics to be poached by ambulance services interstate or to change careers entirely.
A 2021 survey of Victorian paramedics found 74 per cent of respondents were thinking of leaving the profession.