Former prime minister Kevin Rudd supports Australia's bid for a United Nations Security Council seat, but he says the government's first priority should be the economy.
Mr Rudd's comment came as Prime Minister Julia Gillard headed home from New York after making a final pitch to world leaders to support Australia's push for a non-permanent seat on the UNSC.
Opposition Leader Tony Abbott said on Friday the bid had led to Australia's aid being "redirected" to secure votes and jibed in an interview on the Nine Network: "If we can't beat Luxembourg, there's something wrong, frankly."
Mr Rudd told reporters in Brisbane on Friday that the UNSC bid, which he launched four years ago, was always going to be a difficult contest.
"The number one priority for Australia is to make sure we have a strong economy ... (and) the tax revenue to deliver the basic services that Australian people want in health and education ... a clean environment and our national defence," Mr Rudd said.
But he said it was in Australia's national security interest to have a role in the UNSC, and he supported the prime minister's effort to see the bid succeed.
"When I launched the bid in 2008 I made it very plain this would be very, very difficult," Mr Rudd said.
"This is by no means a lay-down misere - it's going to be hard-fought all the way."
Before she left New York, where she addressed the UN General Assembly, Ms Gillard said she had achieved her five targets for the trip, including supporting UN-led anti-poverty goals.
"I came here with five objectives, and that was to advocate for the Millennium Development Goals; to talk about the importance of peace building; to deliver my address to the UN General Assembly; to meet fellow leaders; and of course to advocate for our Security Council bid," she said.
"I have been able to do all of those five things across the week."
The prime minister refused to speculate on Australia's chances of securing a 2013-14 Security Council seat at a secret ballot of 193 nations to take place on October 18, describing it as a "tight and tough" race.
But she said, whatever the result, the week at the UN had reinforced to her the fact that Australia was "respected in the world".
Foreign Minister Bob Carr dismissed a report quoting an official saying the bid was "in the bag".
"I would love that interpretation to be true, but no diplomat working for us in Canberra or here has said anything like that. None of them have said anything different from the fact that, at best, it's going to be close," Senator Carr told reporters in New York.
He said competitors for the seats, Finland and Luxembourg, had begun their campaigns much earlier than Australia and secured commitments from other nations long before 2008.
Before she left, Ms Gillard and partner Tim Mathieson visited New York's 9/11 memorial.
The site where two aircraft hijacked by terrorists flew into the World Trade Centre towers, killing more than 2750 people, now contains reflective pools, a tree and new construction.
She also met with Microsoft co-founder and chairman Bill Gates for talks focused on the global fight against polio.