Nervous Nationals MPs are not ruling out a move on their leader, Michael McCormack, before the next election unless he significantly hardens his calls for a taxpayer underwrite of a coal-fired power station.

Key points: Queensland Nationals want Michael McCormack to demand shortlisting of coal generation for taxpayer subsidy

Queensland Nationals want Michael McCormack to demand shortlisting of coal generation for taxpayer subsidy Nationals leader Mr McCormack said the Government would consider supporting coal-fired power if it made financial sense

Nationals leader Mr McCormack said the Government would consider supporting coal-fired power if it made financial sense The news came as Prime Minister Scott Morrison said his Government is "supportive of reliable power"

In what looms as a dilemma for the Coalition, Queensland Nationals told the ABC they want coal generation among the projects shortlisted for taxpayer subsidy by Energy Minister Angus Taylor — and they want Mr McCormack to demand it.

But Liberals said that if coal projects do feature on Mr Taylor's "Underwriting New Generation Investments" list, their party would suffer in city seats.

This includes where sitting Liberal MPs are facing contests from high-profile independents preaching tougher action on climate change, such as Kooyong — held by Treasurer Josh Frydenberg — and former prime minister Tony Abbott's electorate of Warringah.

One Nationals MP said the Coalition junior party was staring at its "worst percentage loss in Nationals history" and nominated the Queensland seats of Dawson, held by George Christensen, Flynn, held by Ken O'Dowd, and Capricornia, held by Michelle Landry, as likely losses, along with the NSW seat of Page, held by Kevin Hogan.

Mr McCormack said the Government would consider supporting new coal-fired power if it made financial sense.

"If the future means building another coal-fired power station or building one indeed in north Queensland, then certainly we'll look at it, if the business case stacks up," he said.

One Queensland National told the ABC that Mr McCormack's support for underwriting a coal project needed to be explicit and without condition.

Six Queensland Nationals wrote to their leader last week calling on him to "take immediate action" to "underwrite new generating capacity [power station] construction for regional Queensland", noting that industry, small business and consumers were at "their wits' end" because of exorbitant energy costs.

Prime Minister Scott Morrison, when asked whether he supported Federal investment in coal-fired power, replied: "We're supportive of reliable power — I've already made a number of announcements in this area.

"We're technology and resource agnostic when it comes to ensuring that we have reliable power."

Former Nationals leader Barnaby Joyce supports underwriting new coal-fired generation.

Mr Joyce told the ABC he would be a contender if there was a vacancy — but insisted he would not be calling for a leadership spill.

Former Nationals leader Barnaby Joyce said he has "no intention of spilling the numbers". ( ABC News: Matt Roberts )

"I was elected by the Australian people as Deputy Prime Minister. I've got no intention of spilling the numbers … but I do say if the position was vacant then of course I'd stand," he said.

The Nationals partyroom next meets at 10:00am on April 1, the day before the Federal Budget.

One supporter of Mr Joyce returning as leader said the maverick NSW MP had more cut-through and much greater voter recognition than Mr McCormack.

Some Nationals MPs say they would never support Mr Joyce returning to the leadership — one of them described him as "damaged goods" — and said he would deter female voters from supporting the Nationals.

But another Nationals MP said Mr Joyce would easily have sufficient support to become leader again, if a spill was brought on.