The military regime — which calls itself the State Peace and Development Council — extended the Nobel peace prize winner’s house arrest by one year on May 27. Her latest period of detention began in 2003.
“The NLD will submit an appeal under the law as the extension of Daw Aung San Suu Kyi’s detention was against the law and unfair,” her National League for Democracy (NLD) party said in a statement.
“If the State Peace and Development Council assumes that the extension of the detention of Daw Aung San Suu Kyi was in accordance with the law, we ask them to accept the appeal and open the case in accordance with the law.”
Aung San Suu Kyi was first detained in 1989, and has spent most of the last 18 years as a prisoner at her sprawling lakeside Yangon home, with only brief spells of freedom.
The junta says they are keeping her locked away under a 1975 law to protect the state from “destructive elements”, but legal experts say that under Myanmar law, a person cannot be held without charge or trial for more than five years.
The NLD did not say on what legal basis they would challenge their leader’s house arrest, but also branded the detention of their vice chairman Tin Oo and two other senior party members illegal.
Aung San Suu Kyi led her NLD to a landslide victory in 1990 elections, but ruling junta never allowed them to take office.
Keeping her under house arrest has effectively silenced the woman known here simply as “The Lady,” while leaving her party rudderless.