Liberal Party chooses David Sharma as candidate for Wentworth by-election to replace Malcolm Turnbull

Scott Morrison has kicked off the Liberals campaign for the Wentworth by-election, with the candidate he didn't necessarily want, but who he has thrown his full support behind.

Standing side-by-side with former diplomat David Sharma, the Prime Minister said the party had chosen "the best candidate", despite indicating before the ballot he was keen for a female.

In an early morning tweet, Mr Morrison congratulated former diplomat, David Sharma, calling him a "quality guy with extensive experience and capability."

However Mr Morrison denied he had been embarrassingly snubbed, or rolled, by his own party.

"What I've said is I want to see more women in parliament," Mr Morrison said.

"And I want to see more Liberal women in parliament. And I don't think anyone has a problem with that.

"But you've got to pick the best candidate, and Dave was the best candidate. He has my full support. I want the Liberal Party to decide on their candidate."

Mr Turnbull and fellow former Prime Minister John Howard had both lobbied delegates to pick Mr Sharma over Mr Morrison's choice.

Mr Sharma, the former Ambassador to Israel, must hang onto Malcolm Turnbull's seat at the October 20 poll for the government to maintain its majority.

He has a 17.7 percent margin, but Liberal insiders fear a backlash against the execution of their man Turnbull.

Mr Morrison brushed aside talk of an early election, if the Liberals lose the seat in Sydney's leafy eastern suburbs.

"I'll call a general election in the national interest when it's due," he said.

"What I understand from the Australian people is they expect governments, under whatever circumstances, to serve their term. Malcolm Turnbull had that view. I have that view.

"We'll go to an election next year. That's when it's due."

Mr Turnbull tweeted his congratulations from New York, after yesterday urging Liberals to pick the former Ambassador to Israel.

Mr Turnbull held the seat by close to 18 percent, but Liberals fear a backlash over Mr Turnbull’s dumping, and the bitter civil war raging within the parliamentary wing.

Even Labor candidate Tim Murray conceded Mr Sharma sounds "like a really good bloke".

"His problem is, he's got to sell Liberal Party policies," Mr Murray said.

"And, he'll just be joining a dysfunctional government. By putting him there, it won’t change that."