The owners of Hazelwood are refusing to pay an $18 million bill for the firefighting effort to stop a massive fire at their brown coal mine last year that shrouded the town of Morwell in smoke and ash.

In March, the Country Fire Authority sent an invoice to Hazelwood owners GDF Suez to recover costs from the enormous operation to put out the mine fire, which saw thousands of firefighters deployed into the mine pit to battle the blaze over many weeks.

The open cut mine fire at the Hazelwood plant in Morwell in February 2014.

But it is understood the company last week told the CFA in negotiations that it believed it should not have to pay the $18 million invoice.

That decision was confirmed in a statement released by the company to Fairfax Media on Monday, in which a spokesman said it was GDF Suez's position that it had already paid for the CFA's services through state fire service levy contributions over many years.