Ms McKay told the Daily Liberal: "The state government's budget papers show that Fire and Rescue NSW and the Rural Fire Service combined are facing a $40m budget cut - a cut that will mean fewer people on the ground to fight fires and less budget to do it with."

NSW Treasurer Dominic Perrottet said Jodi McKay had no option but to apologise to emergency services workers and the people of NSW for making a false claim in the midst of a bushfire crisis.

The independent analysis found the budget papers showed recurrent spending on the two firefighting services in 2018-19 was initially estimated to be $1.174 billion. By the time this year's budget was handed down in June, this figure had been revised upwards by $164.7 million (14 per cent), to $1.338 billion.

At the start of 2019-20, spending for the coming year was estimated to be $1.299 billion.

That figure is $39.6 million lower than the previous year's revised estimate, which, while not a like-for-like comparison, accords with Ms McKay's claim.

But RMIT University emeritus professor David Hayward told the ABC initial and revised estimates were not a like-for-like comparison, so "until that final number comes in you just can't make a call" on whether there had been cuts.

Dubbo MP Dugald Saunders said Labor's claims were "false" and "horrible."

"Labor's claims of cuts to budget funding for the NSW Rural Fire Service, as well as Fire and Rescue NSW, are false and the fact that this gets brought up at a time when these agencies are fighting extreme bushfires across the state is just horrible," he said.

RFS Commissioner Shane Fitzsimmons said the organisation has record budgets and has more money now than any other time.