The NSW coroner and an independent inquiry headed by former AFP boss Mick Keelty will investigate the south coast bushfire at Tathra which destroyed 69 homes.
Volunteer firefighters have vowed to oppose any push to create a single fire service in NSW as the emergency services minister savaged the union representing professional firefighters as "bastards".
Recriminations are continuing in the aftermath of the devastating Tathra fire that destroyed almost 100 homes, cabins and caravans on the NSW south coast.
The Fire Brigade Employees Union on Tuesday said an "ongoing turf war" between the professional Fire & Rescue NSW and the volunteer-based Rural Fire Service contributed to the losses in Sunday's blaze.
But the RFS rejects that claim, saying the help offered was an urban pumper that couldn't have accessed hilly terrain.
NSW Emergency Services Minister Troy Grant says the union is pointing fingers based on "part-truths and part-information".
"I am disgusted by this union bastardry that has occurred at a time when people are distressed and suffering," Mr Grant told reporters in Parkes on Wednesday.
The RFS waited three hours to call for FRNSW help as the bushfire raced towards Tathra despite Fire & Rescue offering assistance more than once.
The union says competition between the two fire services "is dysfunctional and dangerous".
But Mr Grant says management is working well together and the union is just stirring the pot before internal elections.
Nevertheless, he's asked former Australian Federal Police boss Mick Keelty to head an inquiry into the call-out procedures for future bushfires "so these questions will never get asked again".
The inquiry, the minister said, was needed to ensure firefighting assets were best deployed to protect life and property.
"What is the best model to make sure that fire appliance are deployed - no matter what badging is on the side of them - where they have the capability, to go to any fire without boundaries being an issue," he said, adding a consolidated "call centre" could be the answer.
The union is open to merging the two services but volunteers insist they'll fight any such push.
"The formation of a single agency would erode volunteer culture and commitment thereby jeopardising property protection throughout NSW," Rural Fire Service Association president Ken Middleton said in a statement on Wednesday.
"Under existing co-operative fire-fighting arrangements there are clearly stated protocols in place for response to incidents within the urban-rural interface."
Mr Keelty will focus on the call-taking and dispatch arrangements of both services.
In 1996 former deputy coroner John Hiatt recommended the services be merged following an inquiry into the 1994 bushfires that devastated parts of Sydney and eastern NSW.
A bitter dispute between paid firefighters and rural CFA volunteers has been raging for years in Victoria.
It's seen a minister lose her job, CFA bosses and then the board sacked, countless court cases and federal government intervention.
A Labor plan to split paid members from the rest of the CFA has now stalled in the Victorian upper house.