Pro-democracy leader Aung San Suu Kyi took her place in Myanmar's parliament on Wednesday, ushering in a historic new political era after nearly a quarter-century fight against military dictatorship.

The 66-year-old Nobel Peace Prize laureate waded through throngs of foreign and local reporters as she entered parliament in Naypyitaw to join a fragile new political system after 49 years of oppressive army rule.

Suu Kyi and 33 members of her National League for Democracy (NLD) party who swept by-elections on April 1 took their seats after backing down from a demand to change the wording of the oath that new members take. Three more will join them in the lower house later.

Asked by Reuters as she walked toward the chamber if this marked an important day for Myanmar, Suu Kyi said: "I think only time will tell."  

She entered the imposing chamber and sat down on her own, near the block reserved for serving military men, who have a quarter of the seats in parliament under the constitution. She seemed relaxed as individual lawmakers strolled over to greet her before taking the oath.

The dispute with the ruling army-backed party over the oath had threatened to upset the delicate detente with President Thein Sein, a former senior general who has overseen a year of sweeping reforms in the resource-rich but impoverished country.

Suu Kyi agreed on Monday to stick to the original wording and she will swear to protect a constitution drafted under military direction that she says is undemocratic and needs to be amended to reduce the political role of the armed forces.

"We've always believed in being flexible throughout the years of our struggle because that is the only way in which we can achieve our goal without violence," Suu Kyi told a news conference in the commercial capital, Yangon, on Tuesday. "I don't think flexibility will be a new concept for us." 

Suu Kyi's entry into Myanmar's political system comes after years of stubborn resistance to the army's attempts to enshrine its grip on power. While Suu Kyi and many of her supporters were in detention in 1990, her NLD swept an election that the military simply ignored. The NLD walked out of the military's constitution-drafting process in the mid-1990s.

The party boycotted a general election in November 2010, when Suu Kyi was again under house arrest, saying the poll was rigged in favour of the military-backed Union Solidarity and Development Party (USDP).

The USDP won an overwhelming victory, but the new government under Thein Sein embarked on political and economic reforms and he persuaded Suu Kyi to enter the political process.

In response to the reforms, Western powers that for years isolated the country over its human rights record, driving it into close ties with giant neighbour China, have begun to lift sanctions. - Reuters