Australia’s leadership roundabout has already been described as a “Muppet Show” by its new prime minister but the nation has now been forced to endure taunts from New Zealand, whose former prime minister said “you're looking a bit like Italy”.

Joking about the difficulties of keeping up with Canberra’s chaos, Sir John Key, who led New Zealand from 2008 to 2016, offered observations on the decision last month by Australia’s ruling Liberal-National Coalition to dump Malcolm Turnbull - the nation’s fourth such coup against a prime minister in eight years.

"I used to say, 'mate, I don't really mind who turns up, just wear a name badge so I know who it is,'" he said.

Sir John, who won three successive elections before retiring because he did not want to be a “career politician”, advised Australian MPs to avoid infighting and pursue “good public policy”.

“I don't want to say it, but you're looking a bit like Italy at the moment," he said at a conference in Australia’s Northern Territory.

"I was the 38th prime minister of New Zealand and John Howard was 24 — you're now up to 30."

Mr Turnbull, who became leader in 2015 after ousting Tony Abbott, was dumped last month by the Liberal party and replaced by Scott Morrison, a devout Christian.