The footage showing the 509 Wyoming crew being engulfed by fire on New Year's Eve went viral. Luckily, all survived.

SafeWork NSW said it was in the process of making contact with Fire and Rescue NSW.

"SafeWork's investigations will, generally, seek to determine the cause and circumstances of an incident and whether risks to work health and safety were appropriately managed, or if further improvement needs to occur," a spokesperson said.

As the bushfires as still ongoing SafeWork said it would "commence preliminary investigations at a later stage".

State secretary of the Fire Brigade Employees Union Leighton Drury said the union was fully supportive of any enquiry but it would need to look at the types of appliances sent into the field and whether they were appropriate.

"Those trucks were over 25 years old some of them, they were old urban pumpers not bushfire tankers," he said.

"They were sent in to go and rescue an RFS tanker which was under threat."

Mr Drury questioned the decision to send in the older trucks which did not have cabin protector systems or roll bars.

"We're not here to witch-hunt people who made the decisions, we want to know why the decisions were made so we don't make them into the future."

The union said defunding by the state government had led to the situation where trucks don't have the right capabilities.

"The Productivity Commission report identified this last week - we get 80 per cent of what Victoria spent on their emergency services and we have one million more people in NSW than in Victoria."

"Firefighting is a dangerous industry so when we get in situations like this it puts firefighters at risk. It's not appropriate for the government to come out and say they've done all they can do."

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The truck in the video was part of Strike Team Golf, a convoy of four Fire and Rescue NSW vehicles sent from HMAS Albatross.

Two of the four trucks had to be abandoned along Hames Road after flames melted their brakes.

"Flash over, flash over our truck is dead," a voice is heard in footage of the incident.

"Once we turned onto Hames Road it turned from day to night in a matter of seconds," one crew member told Four Corners.

All four crews faced horrific scenes that afternoon, one crew whose truck was on fire, decided the safest option was to walk a kilometre down Hames Road.

"To walk a kilometre back to safety would be a quicker, safer option than sitting tight in our burning truck waiting for assistance to come to us - so we got out and put our breathing equipment on," a Fire and Rescue firefighter told Four Corners.

"All four of us were safe and uninjured at this point and we were able to make the walk out."

The fires on New Year's Eve claimed the lives of six people and destroyed more than 380 homes.

Just the day before, Samuel McPaul, a firefighter from Moruya, died when his fire truck rolled in hurricane-strength winds at an NSW-Victoria border town.