Yangon: Supporters of Myanmar's opposition icon Aung San Suu Kyi on Sunday erupted in euphoric cheers after her party said she won a parliamentary seat in a landmark election, setting the stage for her to take public office for the first time.

READ MORE: Suu Kyi: Prisoner-turned-politician

The victory, if confirmed, would mark a major milestone in the Southeast Asian nation, where the military has ruled almost exclusively for a half-century and where a new reform-minded government is seeking legitimacy and a lifting of Western sanctions.

It would also mark the biggest prize of Suu Kyi's political career, and a spectacular reversal of fortune for the 66-year-old Nobel Peace Prize laureate who the former junta had kept imprisoned in her lakeside home for the better part of two decades.

The victory claim was displayed on a digital signboard above the opposition National League for Democracy's headquarters in Myanmar's main city, Yangon, where more than 1,000 supporters began wildly shouting upon learning the news.

"We won! We won!" her supporters chanted while clapping, dancing, waving red party flags and gesturing with thumbs-up and V-for-victory signs.

Earlier, the party had claimed that Suu Kyi was ahead with 65 per cent of the vote in 82 of her constituency's 129 polling stations. The party had staff and volunteers spread throughout the vast rice-farming districts, who were calling in preliminary results by phone to their headquarters in Yangon.

The results must be confirmed by the official electoral commission, however, which has yet to release any outcome and may not make an official declaration for days.