Releasing new overtime and sick leave figures on Tuesday, Ambulance Employees Australia (AEA) said country ambulance officers were doing an average of eight hours overtime a week and taking an average 16 days sick leave a year.
The figures also show Melbourne paramedics doing an average of almost five hours overtime a week and taking an average 13.5 days sick leave a year.
The AEA says the figures, obtained under freedom of information laws from the Metropolitan Ambulance Service and Rural Ambulance Victoria are proof paramedics are dangerously fatigued and need longer breaks between shifts.
AEA Victorian secretary Steve McGhie called on Premier John Brumby to act, with ambulance officers were working so long and sleeping so little, they were sometimes falling asleep at the wheel.
"Premier Brumby needs to fix this problem before someone is killed," McGhie said in a statement.
"After working such long hours and not getting enough sleep, many ambulance officers have told us they've fallen asleep driving and made mistakes at work.
"Some have told us they've even drawn up the wrong drugs and nearly administered them."
The union is battling the ambulance employers, now merged as Ambulance Victoria, for minimum 10-hour rest breaks, compared to the eight-hour breaks they are entitled to now.
McGhie said the data showed the "massive amounts" of overtime paramedics were working.
"It explains why so many say they feel dangerously fatigued," McGhie said.
"Ten-hour rest breaks will mean ambulance officers can at least get a proper sleep before they go to work again."
But an Ambulance Victoria (AV) spokesperson said the union's claim is not reflected in its incident reporting data.
"AV treats paramedic and patient safety as an absolute priority and has been working to address fatigue since late last year."
The spokesman said the state government announced a $187.5 million ambulance services funding package earlier this year, which will deliver 258 extra paramedics, more ambulances and other facilities to regional and rural Victoria.
All extra paramedics will be placed in areas of greatest need, and are in addition to more than 170 paramedics recruited last year.
New roster lines are also being introduced by Ambulance Victoria to address fatigue, reducing the number of nightshifts paramedics work and increasing breaks between shifts.
The union calculates 291 extra paramedics could be employed with the money spent on overtime wages each year.
It said the high levels of sick leave being taken showed paramedics' workload was affecting their health.
Ambulance Victoria, formed when the Metropolitan Ambulance Service and Rural Ambulance Victoria merged this year, and the Victorian government are currently in negotiations over an Enterprise Bargaining Agreement (EBA).
