Fire experts are warning that $512m in congressional budget cuts could leave communities dangerously exposed in an early and active fire season.

Such warnings have sharpened with the early onset of this year's fire season, and the record-setting outbreak in New Mexico.

Experts fear the shortfall will leave fire crews scrambling for resources, and force government agencies to dip into other non-fire budgets to cover the gap.

"A person has to wonder. Is this going to be the new norm – frequent record-setting fires, while the number of federal firefighters and air tankers continue to shrink?" wrote Bill Gabbert, a former fire management officer in the Black Hills of South Dakota who now runs the blog wildfiretoday.com.

A strategic review in 2009 warned the government to step up its fire fighting capabilities to deal with an escalating rise in wildfires, covering up to 12m acres of terrain each year. "The current budget environment for federal and partner fire management is at best uncertain and difficult," the review said.

It noted government agencies had already over-shot their budgets five years in a row, because of escalating wildfires.

But the economic downturn and a Congress dominated by Republicans who want to shrink the role of government make it extremely complicated to divert more funds to forest fighting.

Instead, funding for preventing and putting out wildfires has fallen by $512m, or about 15%, since 2010.

Campaigners say that leaves the federal government agencies responsible for preventing and putting out wildfires under-funded – especially given projections suggesting a rise in wildfires over the next 20 years.

They also worry the government agencies responsible for fire protection are putting capital projects on hold – such as updating its fleet of air tankers.

The number of active air tankers fell from 44 to 14 over the last decade, prompting a group of western Senators to demand the government update the fleet for the coming fire season.

"Concerns have increasingly been raised that the federal agencies responsible for responding to wildland fires – the Forest Service and four agencies in the department of interior – do not have the appropriate number and mix of aircraft that will be needed for wildland fire suppression operations," the letter said.

Ron Wyden, the Oregon Democrat who raised the alarm, told reporters the federal government needed to act quickly to update the fleet for the coming seasons of bigger fires.

"The alternative is to sit around and watch things burn; watch another round of infernos rip through the west," he told reporters.

Fire scientists and conservationists are also demanding the government devote more funds to preventing fires, by reducing the dense forest growth that leads to the super-sized outbreaks of recent years.

The forest service received $317m this year for programmes to reduce dangerous forest growth. That was down from $350m in 2010, and also represents less than one-fifth of the budget for putting out fires.

"The federal government should be investing more money in fire prevention and removing hazardous fuel," said Christopher Topik, director of forest projects for the Nature Conservancy. "That is not an area where we should be reducing."