While Mr Joyce, the Minister for Agriculture and member for New England, is considered a good "retail" politician who relates well to people, there are doubts over his nous in serious policy areas such as economics.



Senator Wong on Thursday said even Mr Joyce's own colleagues had expressed concern about him becoming Nationals leader.

Deputy Nationals leader Barnaby Joyce and Prime Minister Malcolm Turnbull. Credit:Andrew Meares

"Barnaby is pretty entertaining, but he is also erratic, and he simply doesn't have the sober and sensible approach to do public policy that the Australians expect from the holders of high office," Senator Wong said.



Erratic behaviour was "the last thing you want in someone who is one step away from being the PM and who is called upon to act as PM regularly."

Senator Wong cited Mr Joyce's "entertaining" time as opposition finance spokesman, when he mixed up billions and trillions and was repudiated by Reserve Bank governor Glenn Stevens for saying Australia could default on its debts.



"If he can't hold down that job, I don't know how you hold down the deputy prime ministership," Senator Wong said.

Mr Joyce told Fairfax Media if Mr Truss stepped down he would "throw my hat in the ring".