A minority federal parliament could be on the cards, according to the latest polling in the Wentworth by-election.
The Voter Choice research, which sampled 736 voters in the Sydney seat, puts independent Kerryn Phelps on 55.4 per cent of the two-candidate preferred vote, ahead of the Liberals' Dave Sharma.
The Liberals need to retain the seat, previously held by Malcolm Turnbull, at the October 20 by-election to hold onto their one-seat majority in parliament.
In primary terms, Mr Sharma is sitting on 38.8 per cent, with Dr Phelps on 23.5 per cent and Labor's Tim Murray polling 17.2 per cent. The poll has a three point margin of error.
If Dr Phelps, a popular health commentator and local doctor, can get enough preferences from Labor, the Greens and other independent candidates she will have a strong chance of winning.
So far more than 5000 Wentworth voters have cast early votes with 11,000 applying for a postal vote.
The polling came as Mr Turnbull's son urged Wentworth voters not to back the Liberal Party.
Prime Minister Scott Morrison said he disagreed with Alex Turnbull.
"His father disagrees with him too," Mr Morrison told the ABC on Friday.
