The Belarusian public prosecutor’s office requested 12 years in prison for Maria Kolesnikova, one of the main leaders of the opposition movement.
She is accused of wanting to overthrow the authoritarian regime of President Alexander Lukashenko.
The trial of Kolesnikova, 39, which began in early August, comes after months of repression in Belarus.
Thousands of regime opponents have been arrested or forced into exile since Lukashenko’s disputed election last year.
Kolesnikova has been imprisoned for 11 months and is on trial alongside her former lawyer Maxime Znak.
“Kolesnikova and Znak face up to 12 years in prison. The closed-door deliberations took place today and the prosecutor has requested this sentence,” Viktor Babaryko’s press service said in a statement.
The defendants worked for opposition politician Babaryko, who was sentenced to 14 years in prison in July.
Kolesnikova was arrested in September after resisting an attempt by authorities to expel her from the country by jumping out of a car window and tearing up her passport.
The verdict is expected to be delivered on September 6.