KEY POINTS:
The political survival of Opposition Leader Brendan Nelson appears increasingly parlous as knives are sharpened within the ailing Liberal Party.
Despite Nelson's protestations of confidence, an increasing flow of mutinous talk is emerging in major newspapers, claiming a crucial shift in support towards shadow treasurer Malcolm Turnbull.
Turnbull, a former merchant banker and former head of the republican movement, was beaten by Nelson by only three votes in the leadership split that followed the defeat of John Howard's Coalition Government last November.
Although he has repeatedly said he is not about to challenge Nelson, Turnbull has never ruled out aneventual run at the leadership.
His ambition for the job makes a renewed duel between the two inevitable.
Last week Nelson, who has suffered a long run of criticism of his style and performance as liberal leader, received another, too-familiar, bout of bad news.
A Newspoll in the Australian showed his rating for preferred prime minister at 9 per cent - barely above his record low of 7 per cent in February - with the Liberals trailing Labor by 18 percentage points in the two-party preferred vote.
A Morgan poll held even worse news for the Opposition, giving Labor a huge 27-percentage-point lead.
Nelson has not been able to dent Prime Minister Rudd's stature - his support as preferred prime minister runs at 73 per cent - and has failed to impress many Australians with his down-home, frequently bumbling, style of leadership.
He was thrashed for his qualified support for Rudd's apology to the "Stolen Generations" of Aborigines, has floundered in attempts to attack Government policy moves, and lost major ground by hammering Rudd for criticising China's actions in Tibet.
The Morgan poll showed most Australians supported Rudd.
"The telephone poll was taken immediately after [his] high-profile meetings in China with university affiliates and students, and government officials, which has reflected well on his international diplomacy skills," pollster Gary Morgan said.
The latest bout of speculation about Nelson's dire future was sparked by the Weekend Australian, which said key Liberal powerbrokers had switched allegiance to Turnbull.
It also said that rather than allowing Nelson a year in which to prove himself, they had set performance deadlines that could see him ousted within months.
These included Nelson's response to the May 13 Budget, and the outcome of the byelection for the marginal Victorian seat of Gippsland, vacated by retiring National frontbencher Peter McGauran.
Later reports have indicated that indigenous affairs spokesman Tony Abbott, who challenged for the leadership after the election but withdrew before the vote, has abandoned Nelson.
Abbott's six supporters shifted support to Nelson, suggesting deep trouble for Nelson if the leader does have to face a challenge from Turnbull.
OPPOSITION LEADER
* Brendan Nelson is Australia's Leader of the Opposition and leader of the Liberal Party of Australia.
* A medical doctor, he has been an MP since 1996 and Leader of the Opposition since Kevin Rudd's Labor Party took power in last year's federal election.
* He set a record low for Australian "Preferred Prime Minister" for any Opposition Leader in February with 9 per cent in a Newspoll poll. Last month that dropped to 7 per cent.
* Nelson is a fan of electric guitars and fast motorbikes and used to wear an earring.
