The busts of every Australian prime minister can be found in Ballarat's Prime Ministers Avenue, but the recent quick succession of leaders has dried up funds and left Ballarat council two busts behind.

With the recent brutality of Australian politics, which has seen five prime ministers dispatched from office in almost as many years, the money ran out after Australia's first female prime minister, Julia Gillard.

The Prime Ministers Avenue, found in the Ballarat Botanical Gardens, was started almost 80 years ago by Richard Crouch, the former federal member for Corio.

Historian Dr Anne Beggs-Sunter, from Federation University, said Mr Crouch also left a bequest of 1,000 pounds [AUD$1,763], which was to be held in trust and the interest used to pay for more busts.

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The last bust to be completed, Julia Gillard, cost $12,000 — but Des Hudson, the Mayor of Ballarat, said the total price tag was closer to $50,000.

"There's obviously some money which is spent on getting the artist to and from, whether it be Canberra, their parliamentary office ... where they go and observe," Mr Hudson said.

The cost of the rapid turnover of leaders has the council worried.

"When you know that, gee, there's been another prime minister and we've got to allocate $40,000 or $50,000 towards that project, it reduces your capacity to do other things," Mr Hudson said.

"So, what we want are good stable governments in for a while."

Edward Gough Whitlam bust in Ballarat ( ABC News: Danny Tran )

That ferocious pace has kept sculptor Peter Nicholson busy in recent years.

In order to capture the likeness of Bob Hawke, Paul Keating, Malcolm Frasher, John Howard, Kevin Rudd and Julia Gillard, Mr Nicholson met with the political giants to take videos and measurements.

"I had a bit of a jumpy start with Kevin Rudd," Mr Nicholson said.

Kevin Rudd bust in Ballarat ( ABC News: Danny Tran )

"When I finally got the appointment and arrived there, it was the very morning of the global financial crisis and he had a car waiting outside to take him down to Sydney to meet with all the top bankers.

"He was extremely jumpy, he was like kind of an athlete in the Olympics who's about to do 100 metres."

The meetings were done in an effort to get each Prime Minister's measure. A calliper was also used to get their measurements, which yielded curious details.

"Bob Hawke had a very big head in general," Nicholson said.

Bob Hawke bust in Ballarat ( ABC News: Danny Tran )

"Julia Gillard had a very long measurement from the back of her head to the tip of her nose.

"Every single Prime Minister was extremely good natured. Not one of them thought I was going to assassinate them or anything like that."

Mr Nicholson said Australia's first female Prime Minister, Julia Gillard, was his favourite personality.

Julia Gillard bust in Ballarat ( ABC News: Danny Tran )

"She stood up to a hell of a lot of crap from everywhere, from her own party, from the media and, although she had some bad moments, she kind of stuck to her guns if you know what I mean," he said.

"I wanted somehow to project that idea into the portrait which I think I did. I hope I did."

Funding needed to add Tony Abbott and Malcolm Turnbull

While no one has yet been commissioned to do the current Prime Minister's bust, Mr Nicholson said they would have a lot to work with.

"Well Malcolm Turnbull has about three or four different things," he said.

"He's got that crooked nose, the big hooded eyelids, he's got one ear that sort of sticks out."

But at the moment Malcolm Turnbull's bust waiting in the queue, with Tony Abbott's still outstanding.

Dr Beggs-Sunter said it would be natural for the Federal Government to become involved.

"Given that it is a memorial to prime ministers then I think it's perfectly conceivable that the Federal Government should step in," she said.

A spokesman for the Federal Arts Department said it had not received any applications for assistance, but the project could be eligible through funding programs.