Alongside the military preparations to send a peacekeeping force into East Timor, aid agencies have been gearing up to move in hot on the heels of the soldiers.

They are anxious to return in force on the ground to provide food and health care, and deal with what they fear could be a major problem of disease.

Lyndall Sachs, of the UN High Commission for Refugees (UNHCR), says the suspected level of destruction in the territory means shelter will be another crucial concern.

Agencies in Kosovo were unprepared for the speed in which refugees packed up and returned home

"If there's been large scale damage to the homes and dwellings of the East Timorese population, the international community, particularly bearing in mind the monsoons are going to start shortly, will have to bring in large amounts of plastic sheeting so we can get these people out of the rain and into some sort of habitable accommodation," said Mr Sachs.

The agencies will need to learn from past mistakes. In Kosovo, they were unprepared for the mass return of refugees.

What will happen in East Timor will depend in large part on how quickly the multinational force can establish peace and win the confidence of the refugees.

Aid agencies may have to face similar issues to those in Rwanda

Mark Hoffman, of the London School of Economics, says the aid agencies will have to work closely with the military, while at the same time maintaining a discreet distance.

"On the one hand it's crucial for them to have the peacekeeping forces there in order to provide and secure the situation on the ground," said Mr Hoffman. "On the other hand, they need to maintain some kind of distance because they don't want to be caught up and identified as the humanitarian arm of a military operation."

Logistics for both the peacekeepers and humanitarian groups will be a major headache. As well as security, the agencies will be looking to the military for help with transport and to rebuild East Timor's infrastructure.

Mr Sachs says the agencies need to be sure they will not get pushed aside in the early stages as the military moves in.

Agencies won't want to be seen to give aid to those who are going to be engaged in political violence

"We've been co-ordinating with the multinational force in Darwin over the past few days to ensure that there is the humanitarian space created for the aid effort to resume as quickly as possible," said Mr Sachs.

"We are setting up the necessary co-ordination in terms of air cells so that we can ensure the space on the flights going in to Dili and into Baukau, which is the other main airport in East Timor."

As well as conventional air drops, the UN's World Food Programme (WFP) plans to use its new 'snow drop' system for the first time. This allows planes to fly at high altitude, dropping small wing-shaped food packages without the risk of causing injury or damage on the ground.

But they will still rely on advice from observers on the ground about whether the drop zones are safe from militia attack. However, the WFP acknowledges this is only a temporary solution.

Political calculations

"Air transport is very costly, it is the most expensive way of delivering food, so we're very sensitive to this issue," said Trevor Rowe, spokesman for the WFP.

"In the initial stages of a crisis when people are acutely hungry, you have to rely on aircraft if you can't get to the hungry. However, we will eventually begin reliance on overland transport so that we can spread out. This will depend again on the conditions on the ground because all of this is contingent on some kind of security."

There may be other political calculations to confront too. The LSE's Mr Hoffman says aid agencies may face similar issues to those in Rwanda, where they were criticised for providing assistance indiscriminately - and unwittingly - for both the victims and the perpetrators of genocide.

"Because of the pro-Jakarta militias and the mixed nature of the refugees, it may be problematic for the agencies in terms of giving humanitarian assistance, that they don't be seen giving food to those people who are going to be engaged in acts of political violence."