Burma's long-time democracy icon Aung San Suu Kyi has officially been sworn in as a member of parliament, taking public office for the first time after spending much of the past two decades under house arrest.

The Nobel laureate on Wednesday took the oath of office to enter Burma's lower legislative house, ending a parliamentary boycott that had threatened to interrupt the country's political reform process.

For over a week, the 66-year-old opposition leader and her National League for Democracy had refused to take the oath because it required them to “safeguard” the constitution, which was drafted by Burma's former military rulers.

But the NLD earlier this week agreed to take the pledge, while vowing to push for constitutional change through legislative action. Aung San Suu Kyi said Tuesday that compromise was necessary for the sake of reform.

“We have always believed in being flexible throughout the years of our struggle, because that is the only way we can achieve our goal without violence. So I do not think flexibility is going to be a new concept for us.”

The United States on Tuesday welcomed the move. State Department spokesperson Mark Toner said the U.S. hopes Burma's government and its opposition groups will work together to “build on the democratic progress that has been made.”

The NLD, which won 43 of the 45 available seats in Burma's April 1 by-elections, now becomes the main opposition party in a parliament that is still dominated by military-backed political parties.

Aung San Suu Kyi's party won a landslide victory in general elections in 1990. But military leaders at the time refused to relinquish power and the victors were refused entry into parliament.

The NLD boycotted the 2010 elections that ended decades of military rule in Burma.

Since then, President Thein Sein and his new nominally civilian government has enacted a series of democratic reforms, including easing press restrictions and releasing some political prisoners.