In a historic move last week, the lower house of parliament, the National Assembly, voted overwhelmingly to impeach Gachagua on 11 charges including corruption.
The 59-year-old has denied all allegations and will continue to serve in his role until the Senate decides whether to approve his removal.
Gachagua filed the court challenge to stop the upper house’s proceedings set for Wednesday and Thursday, arguing that his impeachment had been unfair and fast-tracked.
The Chief Justice Martha Koome had empanelled a three-judge bench to hear and determine a case consolidating six of the petitions.
Gachagua, a powerful businessman from Kenya’s biggest tribe, the Kikuyu, weathered previous corruption scandals to become deputy leader as President William Ruto’s running mate in a closely fought election in August 2022.
But in recent weeks, he has complained of being sidelined by the president and had been accused of supporting youth-led anti-government protests that broke out in June.
Gachagua, who is accused of threatening a judge among his impeachment charges, on Sunday said he pinned his hopes on the judiciary.