US Secretary of State Hillary Clinton demanded her immediate release, saying she was "deeply troubled" by the "baseless" charges against her.
Other world leaders have also expressed concern over Ms Suu Kyi's detention.
She faces trial on Monday for breaching the terms of her house arrest after an apparently uninvited visit by a US man.
'Tenuous pretext'
"We call on the Burmese authorities to release her immediately and unconditionally along with her doctor and the more than 2,100 political prisoners currently being held," Mrs Clinton said.
 |   |
Ms Su Kyi's party, the National League for Democracy (NLD), which won a landslide election victory in 1990 only to be denied power by the military, "strongly condemned" the charges, which come two weeks before her latest detention was due to expire.
British Prime Minister Gordon Brown earlier said he was "deeply disturbed" by the charges and he accused the Burmese military government of seeking "any pretext, no matter how tenuous" to extend the detention.
The EU special envoy to Burma, Piero Fassino, said there was "no justification" for the detention.
Thailand's prime minister also expressed concern on behalf of the Association of South East Asian Nations (Asean), one of the few groups that allow Burma as a member.
"We would like to see positive steps being taken," Thai Prime Minister Abhisit Vejjajiva told Reuters, adding that the group was "concerned" by the recent events.
