If United States President Barack Obama asks for Australia to send more troops to Afghanistan, there is no reason why Prime Minister Kevin Rudd cannot say no, a strategic policy analyst says.

Mr Obama has reaffirmed his commitment to the ongoing battle in Afghanistan and when Mr Rudd meets Mr Obama for the first time at the White House next month, it is likely he will be asked to send more Australian troops to Afghanistan.

Mr Obama has ordered another 17,000 US troops to Afghanistan and is conducting a review of policy in the region.

Australia currently has about 1,000 troops deployed in the war-torn country.

Professor of strategic studies at the Australian National University and visiting fellow at the Lowy Institute, Hugh White, has told ABC Radio's AM program he believes the troop request will be very close to the top of Mr Obama's agenda.

"Obviously he's got some big issues on his plate, [including] the global economic crisis," Professor White said.

"But behind that, I think Afghanistan is probably the biggest concern he has and I think it's one in which he's very much going to be looking for a response from Australia.

"And the Government here has been saying that we're already contributing and other countries should do more, but I think from Obama's point of view persuading Australia to make a bigger contribution is likely to be a very high priority.

"So I think Kevin Rudd will be very lucky if he gets out of the Oval Office without having that question put to him."

Professor White says Mr Rudd can follow former prime minister Bob Hawke's example and say no to Mr Obama's potential request.

"He should first of all try to get a really clear answer to how is this going to work," Professor White said.

"In what way are the extra troops going to be used? How confident are we that it's going to deliver an effective result within one year or two years or three years?

"If Barack Obama doesn't have a good answer to that question, then I think the best thing for Kevin Rudd might be to say 'No, we're not going to put more troops in'.

"That will be a tough thing to say, but that is sometimes the sorts of choices you have to make.

"One can say no to the Americans. Bob Hawke did, under very important circumstances, for example, on support for SDI (Strategic Defence Initiative)."

But Professor White says it will be tough to turn Mr Obama down.

"If [Mr Rudd] wants to develop the kind of close, personal relationship with Barack Obama that John Howard had with George Bush, I think it will be very hard for him not to say yes, and I think Kevin Rudd probably does have that ambition," he said.

"On the other hand, he'll want to be very careful to ask himself and to ask Barack Obama whether there's much chance of this new strategy in Afghanistan.

"I've got to say myself, I'm very sceptical."

'Terror central'

Professor White says he does not think it is inevitable that Mr Rudd, who once who dubbed Afghanistan "terror central", will say yes, but he will certainly be under pressure.

"[Mr Rudd] faces very sober decisions," he said.

"Afghanistan's a very dangerous place. A decision to increase Australian forces would be a decision to increase Australian casualties.

"And that's a very tough choice for a prime minister to make. He'll want to be very sure that the decision he takes genuinely reflects deep Australian strategic interests."

Professor White says Mr Obama definitely wants more troops from NATO and more troops from Australia.

"And whilst the Australian Government makes a big point of saying 'We're the largest non-NATO contributor,' that's true," he said.

"But we're still one of the smallest contributors, and I think Barack Obama is likely to think that a country of Australia's scale should be making a bigger proportionate contribution.

"And what's more, he's committed to quite a substantial surge of American troops, an additional 17,000 American troops.

"Most of the experts agree that's not going to be enough to implement the strategy he's envisaged, so he's going to need larger numbers of troops from a whole lot of contributors and it seems very unlikely that he'll be able to get that if he doesn't get some more from Australia.

"Barack Obama has really committed the credibility of his presidency to his capacity to persuade other partners, NATO and non-NATO, to increase their contributions in Afghanistan. So I think he's going to be pretty keen to pop the question and very reluctant to take no for an answer."

No long-term presence

Meanwhile, Mr Obama says the US has no desire for a "long-term" military presence in Afghanistan despite plans to send more troops to the war-torn country.

"One of the things that I think we have to communicate in Afghanistan is that we have no interest or aspiration to be there over the long-term," Mr Obama said in an interview with PBS public television.

"There's a long history, as you know, in Afghanistan of rebuffing what is seen as an occupying force and we have to be mindful of that history as we think about our strategy," he added.

Mr Obama earlier announced an end to US combat operations in Iraq within 18 months.

Based on an AM report by Alexandra Kirk and wires