Gachagua, who denies all the charges, backed President William Ruto in his 2022 election win and helped secure a large block of votes from the populous central Kenya region.
The deputy president says he has since been sidelined, amid widespread reports in local media that he has fallen out with Ruto as political alliances have shifted.
Ruto dismissed most of his cabinet and brought in members of the main opposition following nationwide protests against unpopular tax increases in June and July in which more than 50 people were killed.
The high court has declined a request by Gachagua to halt the impeachment proceedings, initiated by Ruto’s coalition allies a week ago. Gachagua, who has refused to resign, was expected to defend himself in parliament later on Tuesday.
“I am innocent of all these charges,” Gachagua told a press conference late on Monday and offered a detailed denial of the allegations, which include amassing a large unexplained property portfolio, and promoting “ethnic balkanisation”.
“I have no intention whatsoever to resign from this job. I will fight to the end.”
Almost two thirds of people who took part in a public consultation last week approved of Gachagua’s impeachment, lawmaker Millie Odhiambo told parliament on Tuesday as the hearing began.
Ruto has not commented publicly on the impeachment proceedings. More than 80% of lawmakers signed up to launch the motion on Oct. 1.
If the national assembly votes by more than two-thirds to impeach Gachagua, the senate will be asked to uphold the motion.
Gachagua outraged many in Ruto’s coalition for likening the government to a company and suggesting that those who voted for the coalition had first claim on public sector jobs and development projects.