YANGON (AFP) – Military-ruled Myanmar is set to release the elderly deputy leader of Aung San Suu Kyi's opposition party when his house arrest term expires this weekend, an official said Friday.

Tin Oo, 83, vice chairman of the National League for Democracy (NLD), has been detained without trial since he was arrested with Suu Kyi after an attack on their motorcade during a political tour in 2003.

"U Tin Oo will be released tomorrow (Saturday) as his detention period is complete," a government official told AFP on condition of anonymity.

A week ago, the NLD said it was expecting Tin Oo's release and said he would resume his political activities.

Tin Oo, a retired general, was transferred from prison to house arrest in Yangon in February 2004 under an anti-subversion law.

The NLD won a landslide victory in 1990 elections but the junta never allowed it to take office. Party leader and democracy icon Suu Kyi, 64, has been detained for most of the past 20 years.

Her detention was extended by 18 months last August after an American man swam to her lakeside home uninvited.

Earlier this week Suu Kyi told her lawyer and NLD spokesman, Nyan Win, it was too early for the party to decide about taking part in elections expected this year, while freedom of expression and information remain elusive.

Myanmar's ruling junta has promised polls as part of a so-called roadmap to democracy, but no date has been set and critics say the plans are simply designed to entrench the generals' power.

The elections, which analysts predict will take place in October or November, would be the first held since the ones in 1990.

On Friday, Senior General Than Shwe made a speech in the remote capital Naypyidaw to celebrate Union Day, which marks the 63rd anniversary of the nation's unification.

"Now, according to the state's seven-step roadmap, a free and fair election will take place soon," the junta supremo said.

Myanmar's 2008 constitution bans Suu Kyi from holding elected office, while reserving a quarter of the seats in parliament for serving soldiers.