Aug. 21 (Bloomberg) -- The party of Myanmar opposition leader Aung San Suu Kyi is ``very concerned'' about her health after she failed to show up yesterday for a meeting with a United Nations envoy, said National League for Democracy spokesman Nyan Win.

Suu Kyi, 63, was due to meet with Ibrahim Gambari, a UN representative on a five-day mission to push for reconciliation between opposition groups and the military, which has ruled the country formerly known as Burma since 1962.

``The government didn't give an explanation for why she didn't show up and neither did Mr. Gambari,'' Nyan Win said by phone from Myanmar. ``We are very concerned about her health because we have no access to her.''

Suu Kyi, who has been detained for 12 of the past 18 years, was suffering from low blood pressure and was unable to leave her bed, Japan's Nikkei news agency reported yesterday, citing an unidentified person close to the military regime.

Suu Kyi underwent gynecological surgery in September 2003 and was hospitalized in 2006 for a stomach ailment. The junta stopped allowing her physician to visit her home for monthly medical checkups earlier this year, NLD member Soe Aung said by telephone today from Thailand.

``It's been quite a long time since her doctor visited her,'' said Soe Aung, who was elected as a lawmaker in 1990 elections that were rejected by the junta when the NLD won. ``She's not getting proper care.''

Gambari's Visit

It is Gambari's fourth visit to Myanmar since the junta deployed soldiers last September to quash pro-democracy protests in the former capital, Yangon. The UN says at least 31 people were killed.

The UN is calling on Myanmar's generals to commit to democratic change and release political prisoners. The Bush administration, which leads international criticism of the regime's human rights record, says the junta has backtracked on a promise to pursue national reconciliation and hasn't met with Suu Kyi since January.

``So far we haven't seen the UN or Mr. Gambari come up with timeframes for the release of political prisoners like Aung San Suu Kyi and dialogue with opposition groups,'' Soe Aung said. ``Mr. Gambari must show the generals that the UN means business or his trip will be worthless.''

To contact the reporter on this story: Daniel Ten Kate in Bangkok at dtenkate@bloomberg.net

Last Updated: August 20, 2008 23:59 EDT