BANGKOK, April 29, 2009 (AFP) - Survivors of Cyclone Nargis are at risk of being abandoned one year on, as Myanmar's junta threatens fresh curbs on foreign aid workers and donors hold back for political reasons, experts say.

Myanmar's military regime drew harsh condemnation when it initially refused to let international aid professionals into the country after the May 2-3 storm, which left at least 138,000 people dead or missing.

The generals eventually relented after an appeal by UN chief Ban Ki-Moon, but aid officials say that many of the 2.5 million people affected by the disaster are without long-term shelter and lack food security.

He said that the survivors of Nargis, which washed away whole villages in Myanmar's impoverished Irrawaddy delta, had received "about a tenth" of what people in Indonesia's Aceh did after the 2004 Indian Ocean tsunami.

Although the UN's flash appeal for the cyclone was 66 percent funded with 315 million dollars last year, some donors are unwilling to fund the appeal further, Horsey said, fearing the political impact of their actions.

Myanmar remains under US and European Union sanctions because of political repression and the continuing detention of pro-democracy leader Aung San Suu Kyi.

It faced further criticism when just a week after the cyclone hit, the government held a national referendum on a military-backed constitution, part of a "roadmap to democracy" leading to controversial elections in 2010.

"Like everything in Burma it becomes a little bit political, some groups suggesting it's not an appropriate place to put money," Horsey said.

But he warned against "unrealistic expectations" that came after access was granted to aid workers last May, when some aid professionals hoped the opening up of the country to aid could lead to greater political openness.

"There was overexpectation this could be a huge sea-change both in political and humanitarian terms. It was unrealistic to say a humanitarian response would change political relations but I think it has broken down suspicions on both sides," said Horsey.

"But it hasn't had any major effect in terms of opening up access in other places in the country and certainly not the political realities of the regime," he added.

A body comprising the Myanmar junta, the Association of Southeast Asian Nations and the UN was set up in the aftermath to coordinate the aid response and allow humanitarian workers to access the country within three days.

Officials have for the past year hailed the tripartite body as a sign of progress - but in March the secretive regime said it was time to return to a more stringent visa system.

"We are obviously very anxious at the moment about possible shifts going on," Chris Kaye, Myanmar country director for the World Food Programme, told AFP.

"The whole issue of the visas seems to be indicative of a tightening of access and maybe increasing restrictions in terms of what the international community can do, (but) we are working through this problem as best we can."

The UN's Resident Coordinator Bishow Parajuli said he wanted there to be a "good understanding and a way to support the good work coming in from the international community to help the people of Myanmar."

Aid agencies meanwhile criticised the Myanmar government for not doing enough.

There had been no government assistance for the relatively few landowners in the delta to rebuild their lives - cattle, nets and boats - leaving them unable to provide employment and credit to the landless majority.

"The government has primary responsibility for its own people and it has been doing a lot, and maybe more than it is given credit for, but (it) is inadequate," said Kaye.

He said 130,000 families are still living in tarpaulin shelters despite the approach of another monsoon. The government has built half of the 18,000 homes it promised to, while agencies have built 7,000 and repaired 30,000.

A further 350,000 people still require food handouts, 250,000 of whom will continue to do so until the end of the year.

"Clearly the government could and should be doing more," said Horsey, the former UN spokesman.