Independent Wentworth candidate Kerryn Phelps is "pretending" to be a Liberal and will bring instability to the federal parliament if she wins Malcolm Turnbull's old blue ribbon seat, the treasurer says.
Wentworth was held by the former prime minister with a two-party preferred margin of more than 17 per cent when Mr Turnbull left politics in August.
The Liberals are keen to retain the seat with their candidate and former ambassador Dave Sharma, who's facing off against Ms Phelps and Labor's Tim Murray.
Source: SBS
But Dr Phelps could cause an upset in the seat if voter anger at Mr Turnbull's ousting and replacement by Scott Morrison translates into a protest vote against the government.
"The reality is we have a contest there between Dave Sharma primarily with an independent, who's pretending to be a Liberal but is certainly not," Treasurer Josh Frydenberg told ABC radio on Monday.
"If she is elected it will bring greater instability into the parliament."
Dr Phelps says she wants to be a stabilising force if she wins and has tried to capitalise on the government's recent leadership crisis.
Source: SBS
The coalition holds government by a one-seat majority, which makes a win in Wentworth crucial.
While Dr Phelps has said she wouldn't block supply, she also says the Liberals would have to "behave in a particular way".
Mr Morrison on Saturday urged those who were considering voting for Dr Phelps to "think about that carefully".
"She is clearly running strongly second and if she continues in that place, she can still be a long way behind on primaries and then she can come over the top and win that by-election," he said.
