"We're pretty shocked that the secretary-general seems to have accepted this at face value," Jeremy Woodrum, director of the US Campaign for Burma, told Al Jazeera.
"The regime is willing to talk to them as always but it never seems to lead to any progress. I'm hopeful there could be some progress in the next couple of days but that would be a definite break from history," he said.
"If the military regime lifts checkpoints that allow aid agencies to go into the delta region that was hit by the cyclone, then that would be real progress, but as long as those checkpoints are in place, I have difficulty seeing it as a real breakthrough."
In Myanmar, despite international condemnation, the country's military rulers pressed ahead with a second round of voting in its constitutional referendum across the main city of Yangon and the southern Irrawaddy Delta, both devastated by Cyclone Nargis.
The government says its proposed constitution paves the way for democratic elections in 2010, but critics say it will simply entrench military rule.
Myanmar's military rulers said the first round of voting, held a week after the cyclone and which excluded the areas hardest hit by the storm, showed 92 per cent of voters favoured the charter.
Some villagers in the region complained of intimidation in Saturday's poll, telling Al Jazeera that military officers had come to their homes and ordered them to vote.
The cyclone left at least 133,000 people dead or missing and about 2.4 million people remain in desperate need of food, shelter and medicine.
The UN has launched an emergency appeal for $201m to aid those affected by the cyclone and that figure is likely increase further once disaster relief experts are able to survey the Irrawaddy Delta.
So far, the world body has received about $50m in contributions and about $42.5m in pledges in response to the appeal, said Stephanie Bunker, spokeswoman for the UN Office for the Co-ordination of Humanitarian Affairs.
A donor conference is being sponsored by the UN and the 10-country Association of Southeast Asian Nations (Asean), which is taking the lead in organising the delivery of aid to Myanmar, one of its members.
Surin Pitsuwan, the Asean secretary-general, said he believed donors would show their goodwill, but added that they would be unlikely to honor pledges if Myanmar's rulers failed to follow through on its promises for international access.
"I don't think we have any doubt that there will be a lot of goodwill coming through," Surin said.
"But again it will depend on how we carry out this goodwill, or administer this goodwill, with the co-operation of Myanmarese authorities. We expect no obstacles."