There is fresh speculation former Treasurer Peter Costello has his eyes on the Liberal leadership, after he apparently turned down a high-paying corporate job.
According to Channel Seven, Mr Costello has been offered $2 million a year to head-up the World Gold Council in the UK.
Deputy Liberal leader Julie Bishop dismissed talk of a leadership challenge.
"This is just speculation," Ms Bishop told the Seven Network.
Campaigning in South Australia today, Dr Nelson brushed off questions about his leadership.
"I will be taking the coalition through to the next election," he told reporters.
With Dr Nelson's preferred prime minister rating languishing in the low teens, some Liberals have been urging Mr Costello to challenge for the leadership.
Mr Costello is yet to reveal whether he intends to stay in Parliament, following the resignations of former Howard Government colleagues Alexander Downer and Mark Vaile.
Mr Costello is not expected to publicly announce a decision on his future until his memoirs, which he is writing with his father-in-law Peter Coleman, are released in October.
