The state government's failure to fully implement a plan to send firefighters to treat critically ill patients in place of ambulances is costing lives, experts say.

A leaked briefing shows Health Minister Jillian Skinner and the state's most senior health and emergency services bureaucrats signed off two years ago on the proposal to use firefighters when ambulances cannot reach patients. The move was proposed as a stopgap measure to reduce ambulance response times, after a plan to have the services respond jointly to ill patients stalled because of the Fire Brigade Employees' Union's pay demands.

The Ambulance Service is under pressure to reduce waiting times. Credit:Darren Pateman

But Fairfax Media can reveal NSW Ambulance has referred fewer than 20 cases to firefighters in the past year. This comes despite at least four high-profile cases where patients have died from heart attacks while waiting 30 minutes for an ambulance – or much longer than the eight-minute benchmark.

The ambulance service is estimated to have received more than 8000 of the highest-grade emergency calls in the past year and 2000 cases of cardiac arrest, across NSW.