Deputy Liberal leader Julie Bishop doesn't believe her boss is going anywhere before the next federal election.
Malcolm Turnbull has her support and that of the "vast majority" of the party room to stay on as prime minister, she said on Sunday.
Leadership speculation has reared its head in federal politics once again, with two stories in The Australian citing anonymous senior Liberal MPs pondering ministerial reshuffles, the dumping of Ms Bishop as deputy leader, and possible new tickets including Scott Morrison and Christopher Pyne, Peter Dutton and Mr Pyne, or Mr Turnbull and Mr Dutton.
Ms Bishop was confident Mr Turnbull would lead the coalition to the next federal election, likely to be in late 2018 or early 2019.
"He's a can-do prime minister," she said.
"He's got a vision for this country, he's got a lot of issues to deal with but he's performing strongly and he will retain the support of the vast majority of the party room in order to lead us to the next election."
Ms Bishop's security as deputy Liberal leader came down to the will of the party room.
She saw her role as being responsible to the party room and serving as a conduit between MPs and the leader.
Long-standing speculation that Attorney-General George Brandis will be appointed high commissioner to London was raised once again in The Australian, along with a suggestion Defence Minister Marise Payne could be sent to New York as consul-general.
Ms Bishop rejected the speculation about Senator Payne's future, saying it's never been discussed with her and the first she heard anything was reading the newspaper on Saturday.
"I have no idea the source of that story, I put it down to fake news," she told Sky News.
As to Senator Brandis, Ms Bishop said she had only discussed the ongoing media stories about his future, not the actual appointment - which was the purview of the prime minister.
"The prime minister would say to me, 'foreign minister, I would like to appoint XYZ to a position'," she said.
"I'd have my views but, at the end of the day, the prime minister has the call."
Former New Zealand prime minister John Key, who stepped down in December after eight years in the top job, says he's always been a Malcolm Turnbull fan.
"Australia's had a lot of different prime ministers over the time that I was PM over here and so some stability there I think is useful," he told Sky News.
Mr Turnbull had all the attributes required to lead Australia succesfully.
"He's driven and he's motivated and he's ambitious for Australia," Mr Key said.
"It's no great secret that I really back Malcolm."
The two men have kept in touch since Mr Key left politics.