A former volunteer rural firefighter and "first responder" is suing the NSW Rural Fire Service, claiming he suffers post-traumatic stress after attending hundreds of critical incidents.

Key points: Simon Andrews attended 772 critical incidents between 2004 and 2011

Simon Andrews attended 772 critical incidents between 2004 and 2011 Incidents included a "horrific" attempted suicide and fatal car accidents

Incidents included a "horrific" attempted suicide and fatal car accidents He claims he told the RFS he was struggling but continued to be deployed

In a statement of claim filed to the NSW Supreme Court, Simon Andrews, 48, is seeking millions of dollars in damages because he can no longer work due to chronic PTSD with associated depression and resulting alcohol abuse.

A hearing before Justice Julia Lonergan is set to begin today when Mr Andrews will allege the RFS failed in its duty of care, was negligent and "failed to take any or any adequate care for the safety of the plaintiff".

As a volunteer firefighter, Mr Andrews served in Illawong in Sydney's south and in the south-western suburb of Austral where he was "called out as a first responder," according to the claim.

For his work attending the Austral floods in 2012, he was awarded a commissioner's commendation.

Mr Andrews says he has PTSD and depression. ( ABC News: Philippa McDonald )

In documents tendered in court, Mr Andrews claims he attended 772 critical incidents between 2004 and 2011 as a volunteer fire fighter.

Apart from fires, the callouts included a "horrific" attempted suicide, suicides, fatal car accidents, a semi-trailer fire with exploding gas cylinders and an explosion at a school.

It is Mr Andrews's case that his injury "was the cumulative effect of recurrent exposure to numerous traumatic incidents in which persons were killed or injured" and that it was "foreseeable" that he would develop a post-traumatic stress disorder.

Mr Andrews is on anti-depressants and has been in and out of hospital receiving psychiatric treatment up to twice a year, often for three weeks at a time, according to his claim.

Mr Andrews's wife has also "become increasingly depressed" as a result of her husband's aggressive and abusive symptoms and behaviour, according to a psychiatric assessment by Professor Alexander McFarlane from the University of Adelaide.

Mr Andrews claims he was never screened for his physical or psychological fitness when he joined the RFS.

While he consulted the RFS's Welfare Manager on several occasions, he claims he was never advised to see a doctor or a psychologist and continued to be deployed to hundreds of further incidents.

His case for damages for personal injuries runs into millions of dollars to cover lost wages, superannuation, continual medical treatment and interest.