Firefighters have called for a coronial inquiry after it was revealed a controlled burning operation could have inflamed a fire that ripped through a Victorian town on Christmas Day.

Strong winds and dry conditions fanned the erratic flames of the fire at Wye River and Separation Creek, south of Lorne on the Great Ocean Road, which burned through 116 homes.

It was reportedly ignited by a lightning strike in inaccessible country on December 19, and continues to burn out-of-control.

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Emergency Services Commissioner Craig Lapsley confirmed on Wednesday the state government conducted a backburn operation at the site of the-then half-hectare Wye River fire, just three days before the devastation on December 25.

It may have led to the Christmas Day blaze, Fairfax Media reported on Thursday.

Documents showed authorities were warned the operation, conducted on December 22 as the small fire ignited by lightning on December 19 burned in “deep, inaccessible country” at Wye River, could have catastrophic consequences particularly in light of “very high fire danger ratings increasing temperature and strong winds later in the week”.

The backburn, which included aerial and ground operations, was authorised by government authorities and carried out on December 22 and 23. It was deemed “successful”.

An Elvis helicopter picks up ocean water to protect homes from the Otways bushfires in Wye River on December 31. Photo: AAP

But the Wye River fire had grown in size following the controlled burn, and, although authorities planned to bring the fire out of inaccessible country to an area where it could be controlled, a weather change pushed it over a ridge and towards Wye River.

“This option was discussed and approved at incident, regional and state control levels, which reflects the complexity and difficulty of having a deep-seated fire in a dry forest with excessive fuel loads with potential to increase fire intensity,” Mr Lapsley said in a statement.

“This fuel had to be removed to reduce intensity and fire spread.”

Communities were briefed about the strategy and the difficult conditions firefighters faced.

Mr Lapsley said the risks of the controlled burn were understood by authorities, and it was “judged it would be riskier not to undertake the back burn”.

In past days, calls emerged for an independent investigation into the Wye River blaze, and concerns have now arisen at the governments failure to be forthcoming with details of the backburn.

The state government has promised a thorough investigation by the state’s emergency management inspector-general.

But United Firefighters Union secretary Peter Marshall wants an independent inquiry into the fire, which grew from less than one hectare on December 19 to 4080 hectares once it jumped containment lines on Christmas Day.

He said the investigation was beyond the resources and powers of the inspector-general and said the coroner could hold inquests into non-fatal major incidents.

“Wye River residents are entitled to an independent coronial inquiry,” Mr Marshall said on Thursday.

DELWP (Department of Environment, Land, Water and Planning) was savagely criticised in an investigation to a controlled burn it set in state forest near Lancefield in early October, which ran out of control in extreme weather, burning four homes and destroying 3000 hectares.

– with AAP