Former PMs from both sides of the political divide joined the nation's serving leader Tony Abbott to farewell Mr Whitlam in Sydney's Town Hall on Wednesday.

As they gathered in an ante-room after the service, Mr Abbott rested his arm on Bob Hawke's shoulder as the former Labor PM embraced Julia Gillard, while Malcolm Fraser was nearby.

Paul Keating entered with Kevin Rudd and John Howard was not far behind as he was last into the room.

Ready to pose for history, Ms Gillard asked AAP photographer Dan Himbrechts if he wanted them to stand in any order.

"They came in and stood how they walked in, there was no fuss about where they stood," Mr Himbrechts said.

"They were all more than happy to do it."

They were such easy models it took just over 60 seconds to record the moment.

Despite appearances, there was no sinister motive behind Ms Gillard standing four prime ministers away from nemesis Mr Rudd, although their perfunctory handshake indicated the tension is still strong.

And they sat a few seats away from each other inside the service.

She and Mr Hawke, however, shared a much warmer greeting, while she spent time chatting with Mr Fraser, the arch enemy who took over as Liberal prime minister after Mr Whitlam's dismissal in 1975.

Ms Gillard, Mr Keating and Mr Hawke enjoyed warm cheers from the pro-Labor crowd in the Town Hall, but Mr Rudd received a less enthusiastic welcome.

Mr Abbott and Mr Howard, however, were roundly booed, while Mr Fraser's recent warmth with Mr Whitlam was respected with only muted boos.

But bi-partisanship abounded in the service, with Mr Hawke speaking warmly with Mr Abbott, while Liberal attorney-general George Brandis sat alongside Labor leader Bill Shorten.

Even personal quarrels were forgotten as Mr Keating and his ex-wife Annita arrived and sat together, the first time they'd been seen with each in public in many years.