RANGOON, Burma - The United Nation's special envoy to Burma was expected to meet detained opposition leader Aung San Suu Kyi during a visit to the country that began Saturday, the latest effort to coax democratic reforms from the ruling junta.

The four-day trip by UN special envoy Ibrahim Gambari comes amid criticism that his three-year mission has failed to produce significant results.

The 63-year-old Suu Kyi, who has spent more than 13 of the past 19 years under house arrest, refused to see Gambari during his last visit in August. The snub sent a message that the detained Nobel Peace Prize laureate was dissatisfied with the United Nations' unsuccessful efforts to bring about change in the military-ruled nation.

"I strongly believe that Daw Aung San Suu Kyi will meet the special envoy this time," said Nyan Win, spokesman for Suu Kyi's National League for Democracy party. "Daw" is a term of respect.

It remained unclear whether Gambari would hold talks with Burma's leader, Senior Gen. Than Shwe, who has shunned the envoy during his last three trips to the country. Gambari was expected to meet Foreign Minister Nyan Win later Saturday, officials and diplomats said on condition of anonymity because no official itinerary was released.

U.N. Secretary-General Ban Ki-moon expressed frustration after Gambari's August visit when the junta again ignored the UN's requests to release political prisoners and open dialogue with Suu Kyi. The latest trip marks Gambari's seventh to Burma since he took up the assignment in 2006.

This time around, Ban said he hoped Gambari would have "meaningful discussions with all concerned on all points raised during his last visit," a UN statement said, avoiding direct mention of both Than Shwe and Suu Kyi.

Burma's military, which has ruled since 1962, tolerates no dissent and crushed pro-democracy protests led by Buddhist monks in September 2007. It holds more than 2,100 political prisoners, up sharply from nearly 1,200 before the demonstrations, human rights groups say.

The current junta came to power in 1988 after crushing a nationwide pro-democracy uprising. It held elections in 1990 but refused to honor the results after Suu Kyi's party won a landslide victory.