Mr Hawke surprised many with a shot across the bows of the Gillard government's defence policy, declaring scepticism about the decision to allow US marines to rotate through Darwin.

"I don't think it was necessary, myself," he told compere Ray Martin. "They would deny it's a base ... but that's just playing with the words."

He also rejected suggestions that China's rise should be a cause for alarm, saying "historically, China has not been hegemonistic".

Mr Howard also spoke up strongly for the relationship with China, welcoming Chinese foreign investment.

Both former leaders said Australia should not see itself as having to choose between its alliance ties with the US and its deepening economic relationship with Beijing.

The former political titans were speaking at a fund-raising lunch for Lifeline at Sydney's Westin Hotel, both having previously rebuffed many requests to appear on a stage together.

Asked by Martin why both federal major party leaders were "on the nose" with the public , Mr Hawke suggested lack of "outstanding" political leadership was a problem worldwide, and that the media was part of the problem.

"There hasn't been a point before the present time, since the end of the Second World War, when there hasn't been at least one outstanding political leader in the world," he said.

"Why is this so? One of the reasons, I think, is that ... the media in general [ has ] become much more intrusive into the personal and private lives of people in politics."

"People of talent ... say, 'Why the hell, why should I subject myself to this?'"

Mr Howard disagreed, saying the media had always been intrusive, it was just that now it had "more devices" to be intrusive with.

He said Australian politics had a dead heat for the first time since 1940, and that there was a difference between popularity and authority.

Both he and Mr Hawke had experienced ups and downs in popularity but had never lost authority.

He said Prime Minister Julia Gillard's authority had suffered because she had "unusually" replaced an elected prime minister and had not won the last election in her own right.

"There is a sense in the community that she does not have the authority of an elected prime minister" he said. "When there is an election, I promise you this ... it will be a clear-cut result. We won't get another hung parliament."

On the outbreak of hostilities between Israel and Hamas, Mr Howard spoke strongly in support of Israel's right to defend itself, but said the world wanted a two-state solution.

Mr Hawke said not all blame could be laid at the feet of the Palestinians.

"The Israeli government has been less than responsible to its own self-interest in the way it has encouraged settlements [ on the West Bank]," he said.

He said the US had missed a great opportunity to pour money into the Palestinian economy to make it viable and create hope, which would "change the mindset of the Muslim and the Arab world".

Asked about the prospects of war in the Middle East, he said he hoped Israel would understand that all-out war was against its interests.

"That would spell the death warrant of Israel. If they attacked Iran, there is no doubt in my mind that Iran ... would get a nuclear device and put it into Israel."

The pair agreed on the dismal outlook for Europe and the hopes of an economic resurgence in the US.

Both expressed some disappointment with Barack Obama, Mr Howard saying that the election of the first black American president had been a "magnificent thing" but that Mr Obama hadn't fully delivered.

Mr Hawke said Mr Obama had come in with little experience and had not been helped by inheriting what he described as a "very significantly buggered-up economy".

"Is the world ... better off because it was him, rather than [Mitt] Romney? I would say marginally."

Mostly their old rivalry lay well buried beneath good-humoured banter, though Mr Hawke couldn't resist a dig when Mr Howard stated his flat opposition to gay marriage.

"He's not a bad bloke but he's a real bloody conservative" Mr Hawke declared, to laughter.

Mr Hawke said Mr Abbott was "not a plus" for the conservative side of politics in Australia and that he hoped the Coalition did not replace him.

Mr Howard leapt to the defence of his former protege, saying Mr Abbott's elevation to the leadership had set in train the course of events that led to Kevin Rudd being deposed.

Had Mr Abbott "not become the leader of the party before the last election, Rudd would never have been thrown out by the Labor Party and Rudd would have won the last election with a majority in his own right", Mr Howard said.