Former foreign minister Julie Bishop has taken a swipe at Prime Minister Scott Morrison over his handling of the NSW bushfire crisis, chastising him for his decision to take an overseas holiday while fires ravaged his home state.

At a gathering of prominent Liberal figures just before Christmas, Ms Bishop told the crowd: "The Prime Minister is testing the theory that the best way to resolve a crisis is to be as far away from it as possible."

Julie Bishop addressed a 150-strong Liberal Party crowd from the balcony of Kevin McCann's Mosman mansion.

Four senior party figures who attended the function confirmed Ms Bishop's statements. "She smashed him," one senior MP said.

Ms Bishop was speaking at the annual Christmas party for the Liberal Forum, an unofficial grouping that organises events for the party's so-called "moderate" wing. The soiree was held at the Mosman home of Kevin McCann, a former chairman of Macquarie and Origin Energy and former president of the NSW Liberal Party. He also sought Liberal preselection for the seat of Warringah in 1994 but lost to Tony Abbott.