Malcolm Turnbull says it's up to Tony Abbott to explain his changing opinions on climate change, noting his own stance on the issue has been consistent.
The prime minister said a number of views Mr Abbott aired in a speech to climate sceptics in London this week were "quite different" to those he expressed when leader.
While he understood the interest, he wouldn't say if he was baffled by the turnaround.
"It is a matter for him," he told the Seven Network on Friday.
"He can explain his speech and whether it is consistent or inconsistent."
Mr Turnbull insists the federal government is focused on delivering affordable and reliable energy to Australians, while also meeting the country's international commitment to cut emissions in accordance with the Paris Climate Agreement - which Mr Abbott supported when prime minister.
"As he said at the time, it is right," he said.
"I am consistent. I have been making the same points for a very long time."
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It follows a rebuke from Deputy Liberal leader Julie Bishop, who called on her former boss to offer an explanation for his change of opinion.
"He is entitled to change his mind, but I am sure that is why there is a deal of interest in what he has to say," Ms Bishop said told ABC TV on Thursday night.
"But the important thing is the government's position and under Prime Minister (Malcolm) Turnbull we are working hard to come up with a plan that delivers affordable and reliable energy that will meet our international obligations."
The foreign minister baulked at questions about whether Mr Abbott's constant undermining of the Turnbull government could cost the coalition the next election, or whether he ought be expelled.
Former Liberal leader John Hewson has urged Mr Turnbull to call out his predecessor, especially over energy policy.
