Turnbull back in Sydney after Wentworth by-election

Former prime minister Malcolm Turnbull and his wife Lucy are back in Sydney after the boilover in the by-election for his old seat of Wentworth.

Malcolm and Lucy Turnbull, at his farewell press conference, have returned to Sydney from overseas. (AAP)

Former prime minister Malcolm Turnbull and his wife Lucy are back in Sydney for the first time since spending the weeks since his ousting overseas.

The Turnbulls landed at Sydney airport on Monday and avoided reporters by slipping out through the loading dock, the Seven Network reported.

It follows the huge swing against the Liberal party in the by-election for his old electorate of Wentworth on Saturday, with some blaming Mr Turnbull failure to campaign for candidate Dave Sharma for the bad result.

Independent Kerryn Phelps appears to have cemented her lead in Wentworth, after a late postal vote surge sent the results into doubt

Independent candidate for Wentworth Kerryn Phelps looks set to secure the former PM's seat. Source: AAP/ CHRIS PAVLICH

The margin between the two candidates is back to a more comfortable lead of 1,600 votes in Dr Phelps’ favour.

Prime Minister Scott Morrison conceded voters had taken their frustration out on Mr Sharma over the party's leadership struggles.

"Liberal voters expressed their anger at the parliamentary Liberal Party ... and we copped that fairly on the chin," Mr Morrison said on Sunday.

The Liberal candidate for Mr Turnbull's former seat said he understood voters were still angry about the former PM's rolling.

Dr Kerryn Phelps and Dave Sharma . Source: Getty Images

"The fundamental driver of this vote was really the manner in which Malcolm left office," Mr Sharma told Network Ten on Saturday night.

The campaign was also derailed in the past two by a series of blunders in Canberra, he said.

"There were significant headwinds from Canberra, I'm not going to diminish or discount them," Mr Sharma said.

"This time the headwinds were too strong."

With wires