In court papers filed on Tuesday and seen by Reuters, Ramaphosa argued the 2022 report was "seriously flawed" and should be set aside as the panel misunderstood its mandate and relied on hearsay evidence.
Ramaphosa said he would seek an urgent court order to halt any impeachment process if parliament were to move ahead while his legal challenge is still pending.
Ramaphosa, in office since 2018, has always denied wrongdoing in the affair, dubbed "Farmgate" by local media.
The theft raised questions about how Ramaphosa acquired the equivalent of more than $A800,000 in cash that he said had been stolen from his farm in 2020, whether it was properly declared, and why it was stashed in furniture rather than deposited in a bank.
A wealthy businessman before he became president, Ramaphosa said the money was proceeds from the sale of buffaloes, and a central bank investigation found he had not contravened exchange control regulations.
The scandal has been a major embarrassment for the president, who came to power on a pledge to fight corruption and clean up the image of his African National Congress party.
In 2022, ANC lawmakers blocked impeachment proceedings against Ramaphosa, but earlier this month the constitutional court said the parliamentary vote was invalid and that the allegations should be probed further.
Ramaphosa, 73, has said he respects the ruling and faced down calls from some opponents to resign.
His presidential term is due to end in 2029, and political analysts say he is likely to survive if impeachment proceedings lead to a vote in parliament.
A vote to remove Ramaphosa as head of state would require a two-thirds majority to pass and, even though the ANC lost its parliamentary majority in a 2024 election, it still has about 40 per cent of the seats in the National Assembly. The ANC has reiterated its support for Ramaphosa, increasing the likelihood of him remaining in power.
