The morning sun sparkles on the famous harbour, sports cars line the streets while people sashay about with their shih tzus.

Welcome to Rose Bay — one of Sydney's fanciest suburbs, where the median house price is more than $3 million and units go for about half that.

On one hand, this is an affluent paradise. On the other, it's a battleground.

Rose Bay is the epicentre of Wentworth — the leafy federal seat held by former prime minister Malcolm Turnbull since 2004, on a hefty 17.7 per cent margin.

That buffer is likely to be slashed next Saturday, when people head to the polls in a by-election.

Heading into the Rose Bay pre-polling station last week one woman best summed up the situation with just two words.

"I'm torn," she says.

"I've always voted Liberal, but I don't know anymore."

Kerryn Phelps — the high-profile independent candidate widely regarded as the biggest threat to this Liberal stronghold — was campaigning out the front.

"Tell me your policies," the woman asks her.

Dr Phelps doesn't need to be asked twice.

Kerryn Phelps poses for a snap with a supporter in Rose Bay. ( ABC News: Nick Sas )

The former Australian Medical Association president and prominent same-sex marriage advocate is a polished media performer, and has — by Wentworth standards — a bit of star power.

But she has a mountain to climb if she is to snatch the seat.

Since federation, it has only ever been held by the Liberal Party, or its predecessors.

At the Rose Bay Central polling place, Mr Turnbull raked in more than 70 per cent of the votes at the 2016 election.

But his ousting as Prime Minister in August has left a sour taste for many here.

"I didn't like what happened to Malcolm," the voter at Rose Bay — who asked to remain anonymous — tells Dr Phelps.

If Dr Phelps has star power, then, in equal measure, Liberal candidate Dave Sharma has political power.

Mr Sharma is backed by Mr Turnbull and former prime minister John Howard.

He has been touted as a future PM and was the youngest ever Australian ambassador, at age 37.

Treasurer Josh Frydenberg with Liberal candidate Dave Sharma and Independent candidate Licia Heath. ( ABC News: Dave Sharma )

On the ground in Wentworth, the anger is not directed at him: "He seems like a decent guy," one voter says.

"It's not his fault," says another.

Mr Sharma, who campaigned with Treasurer Josh Frydenburg in Rose Bay last week before chatting to the ABC, acknowledged voters were frustrated.

He said the leadership spills had hurt Australia's international credibility.

But Mr Sharma was keen to talk about the future, not the past.

"If people look at me, my record and the contribution I've made to public service, and the reasons why I'm getting into politics, I'd hope they'd agree that we need more people like me in politics," he said.

"This is a Government that has a one-seat majority with Wentworth, and is a minority government without it.

"I want people to think about who they think can best represent their interests in Wentworth, and who do they think can best contribute to stability and less uncertainty."

A seat comfortable enough to be socially conscious

Mr Sharma is not backed by all the Turnbulls — the former PM's finance executive son, Alex, has regularly taken to social media to implore people in the electorate not to vote Liberal.

Alex Turnbull believes the Party his father led on two occasions has been consumed by conservative forces and infighting.

Sorry, this video has expired Alex Turnbull urges Wentworth voters to ditch Liberal

"Here's the thing about the Wentworth by-election," he said in a Facebook video last week.

"We're going to have an election in 12 months anyway.

"So if you want to send a signal as to which way the Liberal Party is going and your displeasure with where it is going, this is your opportunity."

Dr Phelps has listed "fixing dysfunction in Government" as her number one policy platform — although how she plans to do that from the crossbench remains less clear.

"People are just saying that they've had enough," she said.

"They are sick of the major parties fighting amongst themselves.

"The factional in-fighting and jostling for position within their own parties. People are saying they want politics done differently, and an independent with a strong local voice can do that."

Shortly after his father was rolled as PM, Alex Turnbull took to Twitter to encourage people to fund Labor candidate Tim Murray's tilt, saying it was: "The best bang for your buck you'll get in political donations in your life."

Despite that support in cyberspace, campaigning on the ground has been a little harder for Mr Murray.

He was widely ignored by morning commuters while pounding the pavement around Rose Bay and Bondi last week — something he brushed off as just part of campaigning.

He did, however, receive five "good lucks".

"I'm gonna' need it," Mr Murray said with a smile.

Labor candidate Tim Murray has a laugh with a supporter. ( ABC News: Nick Sas )

"But you know it's possible I could win. Anything could happen."

Mr Murray's plan is to target young professionals in suburbs like Bondi Beach and Paddington, where the proportion of renters is high and social issues reign.

Last week he was handing out how-to-vote cards, which also included a question: "Would you like some responsible climate change policy?"

Mr Murray said it was "the key issue" in the electorate.

"Out of thousands I've spoken to, I reckon one person has said they don't care about it," he said.

Mr Murray, an economist, entrepreneur, local resident and surf life saver at Tamarama, also lists housing affordability and education as his two other priorities.

It is not just Mr Murray jostling for the environmental vote.

Greens candidate and Waverley Council deputy mayor Dominic Wy Kanak was chatting to a group of first-time voters when the ABC arrived.

"They wanted to know about climate change," he said.

Dominic Wy Kanak is a well-known social justice advocate. ( ABC News: Nick Sas )

"It's my number one policy — caring for country is caring for climate — and refugee policy.

"In this community they are more comfortable and able to take a more global view on these things — they have a social conscience."

Mr Kanak, a councillor for nearly 20 years, is a well-known community leader.

Despite that, campaigning was tough going.

"I'm not Australian," a woman with a thick Spanish accent said as she prepared to hit the surf, ignoring his how-to-vote card.

"That's pretty common here," Kanak said. "It's a transient population, and that's why it's tough to read what'll happen. Who knows."

Ian Thorpe, who does not live in the electorate, is bombarded with voting material. ( ABC News: Nick Sas )

Campaign tactics cross over to the dirty side

Mr Sharma is the overwhelming favourite to win the seat, and has positioned himself as part of the solution, not the problem.

"I acknowledge that some people are frustrated and annoyed with politics, but I want to help improve that," he said.

"Undoubtedly this is going to be a very close by-election.

"People who think this is a safe Liberal seat are mistaken."

A priest weighs up the Wentworth candidates who can be assured of a close race. ( ABC News: Nick Sas )

For Mr Sharma, just getting to Saturday's vote was a political fight in itself.

His preselection came despite Prime Minister Scott Morrison's appeal to the seat's Liberal establishment for them to pick a woman.

Adding to the intrigue of the vote is the fact swings at by-elections can be up to double what you might expect to see at a general election.

"I think I can win," Dr Phelps said.

"I think the Liberals think I can win.

"They're taking my candidacy very seriously — putting out attack ads and pulling out all the stops."

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Earlier in the campaign, there were accusations of electoral posters being ripped down.

Dr Phelps gatecrashed a press conference by Prime Minister Scott Morrison — which was subsequently rescheduled — and social media has been awash with advertisements for all sides.

The Liberals have reportedly spent more than $1 million on the campaign — something Mr Sharma refutes.

Speaking at a Rose Bay optometrist which — perhaps fittingly — was opened by Mr Turnbull in 2009, Sharma listed a strong economy, "keeping the country safe" and a string of local issues as his top three priorities.

For Jackie Bassil, the owner of the local florist next door, that was enough to maintain her vote.

"It wasn't nice what happened to Malcolm," she said.

"But I've voted Liberal for as long as I remember. I won't stray."

Back at Rose Bay, another independent candidate Angela Vithoulkas was attempting to woo voters.

"I come from a communist country, I will always vote Liberal," one told her.

Ms Vithoulkas, sporting a bright orange campaign shirt, replied: "I'm not a communist — I'm a small business owner!"

Angela Vithoulkas is a strong campaigner for small business, having run the famous Sydney cafe Vivo for 16 years. ( ABC News: Nick Sas )

Ms Vithoulkas said her role in the by-election was to "shake it up".

"I've never been that delusional to think I was anything more than an underdog," she said.

"I mean, there are more than 20,000 small businesses in Wentworth, who's standing up for them?"

Royal Bakery owner Carlos Torcato, in Rose Bay — a few doors down form the pre-polling booth — is one of them.

He opened his doors four months ago, and has already seen more politicians than most business owners see in a lifetime.

"It's been good for business," he said, after Treasurer Josh Frydenburg dropped in.

"But I don't know what to think about it all. We'll find out soon enough I guess."