Pro-democracy leader Aung San Suu Kyi won a seat in parliament on Sunday, her party said, after a historic by-election that is testing Myanmar's nascent reform credentials and could convince the West to end sanctions.     

Her National League for Democracy (NLD) party announced to loud cheers at its headquarters that the Nobel Peace Prize laureate had won in Kawhmu, southwest of the commercial capital Yangon, raising the prospect of her first role in government after a two decade struggle against dictatorship.

"Daw Aung San Suu Kyi has won," an NLD official announced, referring to Suu Kyi by her honorific title. Myanmar's Election Commission had yet to confirm any results from the by-elections for 45 legislative seats.

The United States and European Union have hinted that some sanctions - imposed over the past two decades in response to human rights abuses - may be lifted if the election is free and fair, unleashing a wave of investment in the impoverished but resource-rich country bordering rising powers India and China.

The charismatic and wildly popular Suu Kyi had complained last week of "irregularities", though none significant enough to derail her party's bid for 44 of the seats. Suu Kyi made no immediate comment on her victory.     

From dawn, voters quietly filed into makeshift polling stations at schools, religious centres and community buildings, some gushing with excitement after casting ballots for the frail Suu Kyi, or "Aunty Suu" as she is affectionately known.

Among her supporters who voted early Sunday in Suu Kyi's rustic constituency of bamboo-thatched homes in Kawhmu, there was little doubt she would win. "My whole family voted for her and I am sure all relatives and friends of us will vote for her too," said Naw Ohn Kyi, 59, a farmer from Warthinkha.

"So far as my friends and I have checked, almost everyone we asked voted for Aunty Suu," added Ko Myint Aung, 27-year shop owner from Kawhmu.

To be regarded as credible, the vote needs the blessing of Suu Kyi, who was freed from house arrest in November 2010, six days after a widely criticised general election that paved the way for the end of 49 years of direct army rule and the opening of a parliament stacked with retired and serving military.

President Thein Sein, a general in the former military junta, has surprised the world with the most dramatic political reforms since the military took power in a 1962 coup in the former British colony then known as Burma.

In the span of a year, the government has freed hundreds of political prisoners, held peace talks with ethnic rebels, relaxed strict media censorship, allowed trade unions, and showed signs of pulling back from the powerful economic and political orbit of its giant neighbor China.

It was rewarded last November when Hillary Clinton made the first visit to the country by a US secretary of state since 1955. Business executives, mostly from Asia but many from Europe, have swarmed to Yangon in recent weeks to hunt for investment opportunities in the country of 60 million people, one of the last frontier markets in Asia. - Reuters