A plan by Australia's federal opposition that would slow the roll-out of renewable power and build a network of nuclear reactors has set the scene for a divisive confrontation on climate policy ahead of an election expected next year.

The opposition policy, unveiled last month, would replace the current government's emphasis on accelerating construction of solar, wind and batteries with one that envisages a greater role for fossil fuels while seven state-owned nuclear plants are built.

Energy analysts say this would lead to significantly higher emissions for at least two decades before significant nuclear power could come onto the grid — a claim the opposition rejects.