AGL's Liddell power station is a "grandmother" plant that shouldn't receive funds more usefully invested elsewhere to improve Australia's energy prospects, Christiana Figueres, the former United Nations climate chief, said.

Ms Figueres, who as executive secretary of the UN Framework Convention on Climate Change oversaw the Paris climate agreement, said time is running out for Australia to get its energy and carbon policies in order.

"The time is short," Ms Figueres told Fairfax Media during a visit to Australia. "I think 10 years of dithering is enough."

Her comments come as Prime Minister Malcolm Turnbull met AGL executives on Monday to discuss the future of Liddell. AGL has said it was committed to shutting the 46-year-old Hunter Valley power plant by 2022, while the government is pressing to extend its life by five years to head off possible electricity shortages.