The state's pollution watchdog will slap charges on the owners of Hazelwood after a two-year investigation into a devastating brown coal mine fire that choked the town of Morwell for 45 days.

Fairfax Media understands the Environment Protection Authority will as early as Tuesday file 12 air pollution charges in the Magistrates Court relating to the 2014 mine fire disaster.

Engie's Australian unit has been charged over an uncontrilled open cut mine fire at the Hazelwood plant in Morwell, February 2014. Credit:Keith Pakenham

It is the latest legal fallout for Hazelwood's owners, who are already facing 10 work place safety charges from WorkSafe Victoria over the same fire, which together carry a collective maximum penalty of more than $10 million.

The EPA will charge several registered holding companies that cover the ownership structure of the brown coal mine and the associated power plant. Hazelwood is majority owned by the French energy giant Engie – known as GDF Suez in Australia – while Japanese company Mitsui & Co has a minority stake.