A Taiwan diplomat is due in a U.S. courtroom Wednesday on charges that she mistreated her Philippine housemaid.

The case has sparked protests and controversy in Taiwan, where officials argue that Liu Hsien-hsien should be covered by diplomatic immunity under a 1980 agreement on relations between the U.S. and Taiwan.

The issue is complicated by questions of Taiwan sovereignty and its ambiguous status as a self-governing entity claimed by China. The United States says Liu, who runs the Taiwan economic and trade office in Kansas City, Missouri, enjoys diplomatic status only for acts performed within the scope of her authorized functions.

Prosecutors charge that Liu hired a Philippine maid with a promise she would be paid $1,240 a month for 40-hour work weeks. Instead, they say, the maid was forced to work 16-hour days and paid only $400 to $450 a month.

The prosecutors say the maid was also confined at times to the house. They say she escaped with the help of a Philippine man whom she met in a grocery store.

Liu is charged with fraud in foreign labor contracting, a felony punishable by up to five years in prison.