Liberal candidate Dave Sharma has slapped down his potential Liberal colleagues, saying he was "appalled" at the way they treated Malcolm Turnbull.

Speaking at a Sydney Morning Herald forum ahead of Saturday's crucial by-election, Mr Sharma said he could understand the "anger and frustration" in the Wentworth election.

Mr Sharma said Mr Turnbull was an "incredibly popular" local member, who had been a "mentor and friend".

Wentworth by-election candidate Dave Sharma has slapped down his Liberal Party colleagues over the axing of former Prime Minister Malcolm Turnbull. (9NEWS)

"I was appalled at the treatment that was metered out to him," Mr Sharma said about the former prime minister's political execution.

And he said he was sympathetic to the local anger and frustration.

It'll be seen as embarrassing to the Morrison Government, as the former diplomat tries desperately to retain the seat and maintain the Coalition's slim hold on majority government.

Mr Sharma said he was 'appalled' at the way Mr Turnbull was treated by his party colleagues and removed from power. (aap)

In a move that is sure to be seen as embarrassing by the Morrison Government, Mr Sharma said he understands public frustration over the spill. (AAP)

Independent candidate Kerry Phelps is pushing the Liberals, despite a 17.7 percent margin in the blue-ribbon seat.

A loss on Saturday would plunge the coalition into minority government.

Labor candidate, Tim Murray, described the by-election as a "sideshow" and said Labor was more interested in putting resources into next year's general election.