In a 16-way race, every bit of luck counts.

Katter's Australian Party candidate Robert Callanan had the first victory on Friday after receiving the number one ballot position for the Wentworth by-election.

"If you look at my policy, and you look at the donkey votes, then I'll win," Mr Callanan said.

ABC election analyst Antony Green said the Katter party's positioning was unlikely to sway the results dramatically in the affluent urban hub.

"Drawing first position on the ballot paper probably helps him get above 4 per cent and get his deposit back but it doesn't have the slightest impact on him getting elected," he said.

While Mr Callanan took out the prized position on the ballot, the number two spot went to Greens candidate Dominic Wy Kanak and third place went to Shayne Higson from the Voluntary Euthanasia Party.

Candidates for Katter's Australian Party and the Greens have taken out first and second position on the Wentworth by-election ballot. ( ABC News: Brooke Wylie )

Liberal candidate Dave Sharma landed ninth position on the ballot, while Independent Dr Kerryn Phelps fell to second last in 15th.

Mr Sharma spent Friday morning campaigning with the Prime Minister for the third straight Friday, trailing the former Bronte local through the electorate's Bondi Beach.

"The biggest issue is about the government in Canberra. Let's be honest, it's a one seat majority at the moment, or it was until Malcolm Turnbull stepped aside," he said.

"This by-election will have national repercussions and national consequences."

His most prominent rival, Dr Phelps, conceded her position might hamper her efforts.

"Being down at the bottom of the ballot might make it a little bit of a harder task from here," she said.

It wasn't the only hurdle, with reports emerging her council colleague and Sydney Lord Mayor Clover Moore was swinging her support — and fundraising power — behind Licia Heath.

Dr Phelps was initially elected to her council role as Clover Moore's party deputy, but resigned after raising concerns over the team's expenses policies.

Asked if the Mayor's decision to back Ms Heath felt personal, she wouldn't be drawn.

Facing backlash for her decision to initially preference Labor above the Liberals, before reversing her position last week, Dr Phelps said she would direct supporters to vote in the way most likely to get her elected.

"This has always been a safe Liberal seat and so it is going to be a steep climb," she said.

"We've seen that there are 16 candidates in this election and so preferences are going to be very important."

Green said the ballot draw would help the Liberal party retain the blue ribbon electorate.

"On balance it's probably a reasonable ballot draw for Dave Sharma the Liberal candidate — he's well above Kerryn Phelps on the ballot paper which means there'll be a general drift of preferences to him," he said.

"But unless it's really close it shouldn't affect the outcome."

Early voting in the seat begins October 2.