Sydney: Australian Prime Minister Kevin Rudd on Wednesday attacked election rival Tony Abbott’s suitability to be a world leader handling complex international crises, 10 days ahead of national elections.

Labour’s Rudd, a former foreign minister who is trailing his conservative opponent in the run-up to September 7 polls, gave a scathing assessment of Abbott’s ability to deal with difficult diplomatic issues such as Syria.

He said he had observed Abbott over a 20-year period in parliament, “19 years as an exceptionally aggressive and negative politician, by any standard in Australian political history”.

“And suddenly in the 20th year, as we get near to an election, we try to tone all that down a bit and play the statesman ... I just think Australians see through that,” he said.

Rudd and Abbott faced off in a third debate on Wednesday evening with the prime minister switching his campaign focus from jobs and the economy to diplomacy and national security as the situation in Syria unfolds.

Australia assumes the presidency of the UN Security Council in September and Rudd has had telephone conversations with the leaders of the US, Britain and France in recent days on what action needs to be taken against the Bashar Al Assad regime.

“I really do question, having known Mr Abbott for a long, long time, if he really has the temperament for that sort of thing,” he said.

“You’ve got to sit back, think calmly, reflect and then work through what the best decision is. And temperament, judgement and experience are quite important.

“He doesn’t have a background in this field.”

Rudd, a former diplomat and foreign minister, justified his personal attack by saying the Australian people had a right to know “what they’re buying”.

“With me, they do, warts and all,” he said.

Asked if he was qualified to take the reins at a time when Australia might be asked to help take action against Syria, Abbott said he was a member of former leader John Howard’s cabinet “and matters of war and peace, of life and death, were before the Howard cabinet on a number of occasions”.

Australia entered conflicts in Iraq and Afghanistan on Howard’s watch.

“I’m not going to get into a competitive character assassination with Mr Rudd,” said Abbott.

“I will leave Mr Rudd to engage in that kind of personal attack. I would simply suggest that if you want to know my character, ask my colleagues. If you want to know Mr Rudd’s character, ask his colleagues.”

With just 10 days until Australia votes, Rudd continues to lag behind Abbott in opinion polls. He conceded he was behind, “but within reach”.

“This is going to be a tough last 10 days of the campaign,” said Rudd, who ousted Julia Gillard in a party room coup in June to re-take the Labour leadership that he lost to her in 2010.

Several senior ministers have resigned since Rudd resumed the leadership, with his first term cut short by the party due to allegations about his difficult personality and work style.

The prime minister went on to win the third and likely final debate of the election campaign on Wednesday evening, with the 105-person audience of undecided Sydney voters giving it to him 45 votes to Abbott’s 38 with 19 undecided and three abstentions.

Two of the three commercial television networks also gave the debate to Rudd in their viewer polls, with only the Seven network favouring Abbott.