The Victorian Coroner will be asked to launch an inquiry into whether the Hazelwood mine operator had sufficient fire-safety systems installed before the toxic blaze broke out, as claims surface that critical equipment had been removed.

The national firefighters union says it will lodge the application to the Coroner on Monday, seeking an investigation to "drill down" the causes and consequences of the mine fire disaster that is burning into its third week.

The fires near Hazelwood power station. Credit:Wayne Taylor

"Firefighters and the community are being put at an unnecessary risk," United Firefighers Union secretary Peter Marshall said.

"There should be an inquiry into what fire protection was there, and find out if it was operable and had been properly maintained."