Cabinet minister Linda Reynolds has struggled to define the federal government's position on investing in coal-fired power stations, exposing an awkward dilemma confronting the coalition ahead of the next election.

Prime Minister Scott Morrison later declared his government was "technology and resource agnostic" while fielding questions about the politically-charged policy area.

Senator Reynolds repeatedly told Sky News on Sunday the government's energy policy was "incredibly clear" but did not provide a clear answer on underwriting coal projects.

The coalition faces a tricky choice going into the election; Queensland Nationals are demanding investment in coal power plants, while some urban Liberal MPs are nervous this could undermine their climate credentials.

"We're supportive of reliable power - I've already made a number of announcements in this area," Mr Morrison told reporters in Sydney on Sunday.

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

Senator Reynolds, who was promoted to cabinet as defence industry minister earlier this month, said she did not deal directly with questions about energy.

But despite repeatedly claiming her government's policy was "black and white" she could not articulate it.

Senator Reynolds floated various arguments when quizzed on the topic, including that coal had a "legitimate place" in the energy mix and contending the key issue was meeting global carbon emission targets.

The minister also questioned whether governments should be spending public money on power at all.

"Why should it be the government's responsibility to invest in power generation?" she posited.

"We are setting the policy for the energy of the future."

Sky News political editor David Speers quickly pointed out the government was investing billions of dollars in the Snowy Hydro scheme, and former prime minister Tony Abbott had advocated for investment in coal.

"It is a legitimate debate that we're having," Senator Reynolds replied.

"There are always ongoing discussions and as you know in relation to high-energy, low-emission coal stations, there is a community debate going on at the moment about that, including at the highest levels of our society."