The head of a top climate agency is casting doubt over the extended operating life of Queensland coal power stations, suggesting they are already struggling to stay online.

Climate Change Authority chair Matt Kean is unconvinced by the Queensland government's decision to keep the state-owned Callide power station open longer.

"The idea that you can extend Callide - which, don't forget, was out for the last couple of years because it didn't work - the idea you can extend that for another 19 years is for the birds," the former NSW Liberal minister said at the Investor Group on Climate Change summit on Thursday.

"So just because they're saying they're going to extend these coal-fired power stations, doesn't mean they're going to work."

The coal-fired power station in central Queensland ha

See Full Page