"Official files have already started disappearing from the state Secretariat," he said while talking to journalists after casting his vote in Viramgam in Ahmedabad district.
Mr Patel said the Bharatiya Janata Party was likely to get around 70 seats.
"The BJP has already accepted defeat -- that is why half of the government is out working in the elections."
The Patidar Anamat Andolan Samiti leader also urged all eligible people to exercise their franchise.
"People should vote to throw out the arrogant from power in Gujarat," he said.
Mr Patel, who has been leading an agitation by the socially and financially privileged Patel community for reservations, dubbed his political activities as a fight also against the atrocities being inflicted on Dalits and the plight of the state's farmers.
Over 20 million voters will choose their representatives from among 851 candidates in 93 assembly constituencies spread across 14 districts in the second phase of the state elections, which is currently under way.