Having charmed the shoppers at Warringah Mall, dazzling retirees in leisurewear and delighting mothers in activewear, John Howard stood in front of reporters to deliver the campaign's best demolition of Labor and Bill Shorten's focus on "the top end of town".

"I detect in the community a lot of growing suspicion that Bill Shorten is after your savings," said the former prime minister, who was there to support the local member and his "friend of 30 years", Tony Abbott.

"They don't want it taken away through taxes by Mr Shorten."

Then Howard appealed to the voters of Warringah, on Sydney's northern beaches.

"They're not the big end of town. I mean, that is an insult to every successful small businessman who has worked hard accumulated a bit and wants to leave it to his kids," Mr Howard said. "I mean that's what this country is all about!"

It was vintage Howard - a nod to Menzies' forgotten Australians, a paean to suburban values, indignation for those who denigrate diligence, and yes, just a little bit old-fashioned in his gendered pronouns.

"That's what people aspire to do! And this fella Shorten is after those people, and he sneers at them, says, 'You're the big end of town', and his putative treasurer Chris Bowen, says if people don't like it, don't vote for us.

"Well I hope that people don't like it and don't vote for it."

There was applause, and not all of it was from the Liberal Party faithful who had gathered for the Howard/Abbott mall walk.

In normal circumstances, a John Howard deployment would occur in a marginal seat.

Warringah, one of Australia's most affluent seats, has been in Liberal hands its entire life, and in Abbott's hands since 1994.

But these are not normal circumstances. Abbott faces a strong challenge from independent Zali Steggall, who is campaigning on a platform of climate change action.

Abbott appealed to voters "who might be inclined to want to protest against things that may or may not have happened inside the Liberal Party".

He said they should "remember someone is going to be the government on Sunday, and it is much better to have a Liberal government than a Labor one".

Steggall, a former Olympian, hopes to harvest votes from disaffected Liberal supporters who believe their local member is destructive to the party and a drag on climate change policy.

But there was little disaffection at Warringah Mall on Monday.

Both former prime ministers were welcomed warmly by shop owners and shoppers, with people stopping to chat to Howard and have their photo taken.

Abbott was only accosted by one hostile voter, who asked him about his climate change policy and then muttered an insult after he moved away.

Abbott bought a sirloin steak from a local butcher, and Howard caused one retiree (Maria Divola, 93) to knock over her cappuccino in excitement.

Ever the champion of personal responsibility, Howard said it was his fault, and bought her another one.