
The prime minister would be the highest ranking official to attend a UN General Assembly since General Maung Aye, currently vice senior general, attended the 50th Anniversary Special Commemorative Session of the United Nations General Assembly in October 1995.
Political sources in Rangoon said Thein Sein was likely to outline the ruling junta's plan to introduce limited political reform in his speech to the assembly.
In recent years Burma has sent its foreign minister to attend the gathering.
An official from the United States embassy in Rangoon said he did not know about the prime minister's decision. It was uncertain whether Thein Sein would meet with US officials during his stay in New York.
The decision to send Thein Sein follows a visit to Rangoon last month by US Senator Jim Webb, Democrat from Virginia, in what some analysts have seen as a slight thaw in the frosty diplomatic relations between Washington and Yangon.
"It may be a significant trip," an observer in Rangoon commented on the prime minister's planned visit to New York.