Turnbull in tangle on Shorten snake jibe

Malcolm Turnbull has been coaxed into tricky territory on talkback radio, fumbling over a question on whether Bill Shorten is a snake.

Melbourne radio host Neil Mitchell prodded the prime minister on the animal kingdom pop quiz after a focus group participant offered the unflattering analogy.

"The focus groups this week the Fairfax group are running said that you are weak and Bill Shorten is a snake," Mitchell put to the PM in a wide-ranging chat on Friday morning.

"Leadership is not seen as overwhelmingly strong in Australia at the moment, is this a crisis of confidence in your leadership and Bill Shorten?"

Mr Turnbull said the opposition leader had a history of saying whatever an audience wanted him to hear.

"I'm not going to compare him to one - any - member of the zoo over another," he told 3AW radio.

"But I would say he is - ah - perhaps even a snake can sometimes move in a straight line."

The prime minister dead-batted suggestions he was weak with a thinly-veiled swipe at his predecessors.

"The truth is I've stuck to all of our election commitments," he said.

"Australians expect their leaders to stick to their promises and we've seen what happens to leaders who don't."

Neil Mitchell asked his guest if this was a reference to Tony Abbott.

"Oh look, I'm not going to ... I was thinking of Julia Gillard as probably the most famous example, but..." Mr Turnbull said before the pair ran out of time.