An overworked paramedic has narrowly avoided death after falling asleep behind the wheel and crashing an ambulance following a nightmare 18-hour-long shift.

The Victorian paramedic had started working at 7am on Wednesday and he was 14 hours into his shift when he was asked to drive to NSW for one last job.

He finished at around 1.30am on Thursday and was driving home when his vehicle hit an embankment at 90km/h and rolled onto its side in Victoria's north-east. 

Ambulance crew managed to free him from the wreckage before flying him to Royal Melbourne Hospital. 

Victorian Ambulance Union secretary Danny Hill said paramedics working 18 hours is not an isolated case and blamed the punishing workload for putting lives at risk.

'This is daily, this doesn't shock us at all,' Mr Hill told Channel Nine's Today on Tuesday.

'This is happening ever single day that paramedics work… four or five hours of forced incidental overtime and it's hard for them to refuse it.'

'But too often they are ramped at emergency departments or responding to very low acuity cases and are often being used as a utility, often to stop the clock for government KPIs and it becomes dangerous,' he said.

Mr Hill said the paramedic had not stopped throughout the entire 18 and a half-hour shift.

At around 9pm the paramedic raised concerns about the number of hours he had worked when they were given one last job interstate.

'They had been ramped at Wangaratta hospital for several hours. At about 9:30pm they said, 'look, we've been going for about 14 hours now',' Mr Hill said.

'And then Ambulance Victoria said, "look, we've got a job across the border in NSW in Corowa and we've got no one else to go". And so the crew went.'

Mr Hill said Victorian crews responding to jobs in NSW is a regular occurrence as there are no resources close to the border.

The paramedic returned to his base in Myrtleford at 12.30am before he dropped a colleague off and headed home.

'He then drifted off and veered off to the left at 90km/h and rolled down the embankment,' Mr Hill said.

He added the paramedic has physically recovered but is distressed.

Mr Hill said he is surprised cases like this don't happen more often due to the heavy workloads. 

'The employer needs to put control measures in place, ensure paramedics get reasonable breaks, that they get off their shift at a reasonable time and they have a manageable workload,' he said.

'We're just not seeing enough improvement in that part of the system.'

A Ambulance Victoria spokesman told Daily Mail Australia they were reviewing the incident.

'Our initial investigations suggest the paramedic and an Ambulance Community Officer were on call when dispatched to a case in Corowa at 9.30pm on Wednesday 26 June, and were cleared off that case at 11.16pm. They were not rostered to an 18-hour shift,' he said.

'AV is reviewing the circumstances, including the movement of the ambulance between arriving back in Myrtleford at 12.39am on Thursday 27 June until the rollover at 1.26am. 

'However, there is no indication the paramedic was dispatched to a case at that time.'