Burma is holding Saturday a second round of a constitutional referendum in areas devastated by Cyclone Nargis on May 3.
The military government had delayed the referendum in the main city of Rangoon, and areas of the Irrawaddy Delta.
However, voting went ahead in the rest of the country a week after the storm hit, prompting an outcry from the international community.
The government has already announced that voters overwhelmingly approved the draft constitution, which it says will lead to general elections in 2010. Opposition and human rights groups say it will only strengthen the military's control.
On Friday, U.N. Secretary-General Ban Ki-moon said Burma's top leader agreed to allow all foreign aid workers into the country to help with relief efforts. So far, Burma's military government has refused to allow most foreign aid workers to enter the country and stage a full-scale relief effort.
Mr. Ban said General Than Shwe also told him international aid could be delivered by civilian ships and small boats. But the ruling military refused to accept aid from American, French and British military ships positioned off the Burmese coast.
International aid workers and foreign officials cautiously welcomed the apparent shift in the country's reluctance to accept their assistance.
Mr. Ban will attend a donor pledging conference in Rangoon Sunday with other U.N. officials and representatives of the Association of Southeast Asian Nations. The Burmese government has asked for $11 billion in foreign assistance.
Ahead of Saturday's vote, Burmese officials announced Friday that Aung San Suu Kyi had cast an early ballot. The officials say the opposition leader gave her ballot to authorities at her house, where she has been under detention for the past five years.
The latest one-year extension of Aung San Suu Kyi's house arrest expires at midnight Saturday.
Burmese leaders say the cyclone that hit May third killed an estimated 78,000 people, and that 56,000 others are still missing. Some information for this report provided by AFP, AP and Reuters.