UNITED NATIONS — As Burma moves to extend the imprisonment of its most famous democracy advocate, Secretary-General Ban is coming under increasing criticism for his failure to confront the regime on political issues.

President Bush and other world leaders yesterday strongly criticized the Burmese military junta’s decision to lengthen the house arrest of Aung San Suu Kyi to a sixth year, even as the Nobel Peace Prize laureate’s American attorney insisted that the extension violates Burmese law. Mr. Ban, returning to New York after a visit to Burma, expressed regret over the junta’s decision.

But the secretary-general defended his decision, in a rare meeting with the country’s military strongman on Friday, to sidestep political issues, including Ms. Suu Kyi’s situation, in favor of concentrating on the immediate needs of the victims of Cyclone Nargis. Mr. Ban said he secured promises from Senior General Than Shwe to allow humanitarian aid workers unfettered access to the country’s hardest-hit areas.

Five days after Mr. Ban made public the general’s pledge, however, just 20 aid workers have been allowed into the remote areas hardest-hit by the May 2 storm, the U.N. humanitarian coordinator, John Holmes, said yesterday in a briefing to reporters. Of 2.4 million people in need of help, outside workers have reached 1 million, he added. Still, the junta has managed to conduct a second round of voting on its constitutional referendum around Rangoon and in the Irrawaddy Delta, two hard-hit areas.

A day after General Shwe met with Mr. Ban, the junta announced that Ms. Suu Kyi’s house arrest would be extended for an additional year. The opposition leader’s American attorney, Jared Genser, said the extension violates the country’s state protection law, enacted in 1975, which allows one-year extensions of a house arrest for up to five years. Ms. Suu Kyi was first detained under her current house arrest in May 2003, and the final extension expired Saturday.

In the meeting with General Shwe, “I was clearly aware of when this house arrest would expire, and I was concerned whether this house arrest would be extended,” Mr. Ban told reporters. But in his meetings with the junta leaders, “I told them that this is a time we should not talk about political issues, but we must talk about humanitarian issues,” he said, adding that his personal adviser on Burma, Ibrahim Gambari, would now resume “the political dialogue” with the junta.

The relations Mr. Ban has established with the junta leaders are “an asset” to the United Nations, the British ambassador to the United Nations, John Sawers, said. However, he added, “you have to bear in mind that the reason that the Burmese authorities were so unresponsive to the needs of their people is because it’s an undemocratic regime; there is a link between the two.”

“You have to walk and chew gum at the same time,” Mr. Genser said. Separating the humanitarian and political dimensions only serves as a “license to the generals to consolidate their power,” he said.

The lawyer said he doubted that General Shwe would meet with Mr. Ban again.