NSW Environment Minister Matt Kean says "no one can deny" that climate change is to blame for the smoke haze choking Sydney as bushfires burn across NSW.

In the state government's strongest comments yet on the link between climate change and bushfires, Mr Kean said: "This is not normal and doing nothing is not a solution".

Environment Minister Matt Kean says Sydney's bushfires and smoke must be a catalyst for change. Credit:Renee Nowytarger

Mr Kean, who spoke at the Smart Energy Summit in Sydney on Tuesday as smoke blanketed the city, said the weather conditions were "exactly what the scientists have warned us would happen".

"Longer drier periods, resulting in more drought and bushfire," Mr Kean said. "If this is not a catalyst for change, then I don't know what is."