A peace deal says Maoist forces must join the Army, but military hard-liners question their loyalty.
A donor conference Sunday pledged some $100 million, but participating nations said aid was conditional on greater access.
Recent events suggest both Tehran and Washington may be willing to engage in dialogue.
United Nations chief Ban Ki Moon arrived Thursday and hopes to meet Burma's leader Gen. Than Shwe today.
Leaders hope their charges of a crime against humanity will push the junta to expand relief efforts.
Burma said Monday it would allow in some Southeast Asian aid workers.
The military regime views foreign aid workers as potential spies or activists' allies.
UN members rejected a proposal Thursday to forgo junta permission and force aid in.