PARAMEDICS across NSW will don yellow vests today to draw attention to what they call dangerous and chronic under-staffing.
The Health Services Union (HSU) claims the state's Ambulance Service is running with 770 fewer full-time positions than necessary.
Staff numbers have remained at a standstill for a decade despite a workload increase of four per cent each year, the union says, and changes to rural rosters have left some paramedics on call for 160 hours straight.
The HSU's acting industrial manager, Tom Stevanja, said existing staffing and roster arrangements left paramedics vulnerable to fatigue and put patients at risk.
"Response times are blowing out and patients are suffering for it," Mr Stevanja said in a statement.
"We've got crews from Singleton responding to emergencies in Muswellbrook because there's no local crew available.
"One officer recently had to respond on lights and sirens 85 kilometres from Macksville to Woolgoolga. In Sydney, the Hunter and the Illawarra there's no cover for paramedics tied up for hours at hospitals."