In the end, it was the issue of gay marriage that split them... well, that and next year's federal election outcome.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 3 seconds 4 m 3 s Hawke, Howard grilled at lifeline lunch ( Samantha Hawley ) Download 1.9 MB

Appearing on stage for a Lifeline fundraiser in Sydney today, former prime ministers Bob Hawke and John Howard appeared more like old friends instead of the political sparring partners they once were.

In the end, it all got too much for the event's compere Ray Martin, who eventually interjected: "With respect, I'm tired of you two agreeing with each other."

It prompted Mr Howard to suggest they move on to more controversial topics.

"What about gay marriage?" Martin asked to much laughter.

"Where do you stand on that, John - we've just had (US President) Obama change his mind, have you changed your mind?"

Mr Howard was adamant he had not shifted position, something that did not take Mr Hawke by surprise.

"He's not a bad bloke, but he's a real bloody conservative," Mr Hawke said, reflecting on his former opponent's stance on the issue.

"I'm very much in favour of the law being changed to enable marriage between gay people," he said.

"I feel very deeply on all issues of discrimination, and in this area of sexual discrimination it just needs to be said straight-forwardly - you can be born with curly hair, you can be born with this gene-disposition towards homosexuality.

"If a person is that way and they want to have the rights of the institutions of our society, they should have them."

With that, Martin moved onto industrial relations laws, maybe sensing the topic would prove fertile ground for reigniting political passions between the pair.

Mr Howard conceded some aspects of WorkChoices - the removal of the no-disadvantage test - were a mistake, but that most of the changes introduced under his leadership were good for the country.

"One of the interesting tests of that is that two months after I left office, unemployment in Australia dipped to 3.9 per cent, the lowest in more than 30 years," he said.

"It's also a fact that in the time we were in government, real wages steadily rose."

'Absurdity'

During a 45-minute discussion in front of a 900-strong audience, the pair discussed issues as diverse as the current conflict between Israel and Hamas, to the rise of China.

Mr Hawke took aim at those who equate China with the Soviet Union of the past, describing such a comparison as an "absurdity" and noting that no country has benefited more from the Asian nation's growth than Australia.

On the perennial debate about foreign investment, Mr Howard said Australians could not expect China to be the country's largest export destination without Chinese companies wanting to take a financial stake in domestic companies.

The West Australian Government has today announced a Chinese company as the preferred developer for a 15,000-hectare parcel of agricultural land in the Ord River area.

Mr Howard says the Chinese bid was obviously the best offer.

"It's been a dream of people for decades that we open up the north for agriculture.

"And if the Chinese can play a role in that, I don't think we should be alarmed.

"I think it's a sign of maturity if we're not alarmed," he said, describing the overall level of Chinese investment in Australia as still "very small".

Differences re-emerge

When the discussion eventually turned to next year's federal election, the political differences between the former leaders re-emerged.

Asked if having Tony Abbott as Opposition Leader was the best thing going for the Labor Party at the moment, Mr Hawke replied: "Well, I hope they don't swap him."

"Sorry Malcolm," he added, referring to former Liberal leader Malcolm Turnbull who was in the audience.

"I haven't come here with the intention of attacking the other side of politics, but I think objectively speaking it is the case... that Tony is not a plus for the conservative forces in this country.

"As distinct from a situation say three months ago where I wouldn't have considered a bet on Labor winning the next federal election, we're moving towards a situation where, with a reasonable amount of odds, I would think it's an intelligent proposition to think about it."

Mr Howard moved quickly to defend Mr Abbott, saying the Coalition's near defeat of a first-term government at the last election was an extraordinary achievement.

"If Abbott had not become the leader of the party before the last election, (Kevin) 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," he said.

"I think Tony Abbott - and I speak as somebody who sat around a cabinet table with him for eight years - I think he'll make an excellent prime minister.

"I still think he'll win, but it's not a foregone conclusion - those things never are."

Both leaders backing their own side, but both hedging their bets.