"No such thoughts are there in me or my party, and please leave me alone," Mani said.
The 80-year-old Mani has been a legislator since 1967 without a break and has presented 11 state budgets. He is considered a seasoned politician. Critics say he is an opportunist.
Mani heads the Kerala Congress (Mani), the third biggest constituent of the Congress-led United Democratic Front. His party has nine legislators.
In the 140-member assembly, the UDF has 73 legislators and the Left 67.
Speculation about Mani started after two members in Chandy's office were booted out and another arrested for their links with a couple who have been arrested on charges of cheating numerous investors in Kerala.
Since the arrests, the Left has organised street protests demanding the resignation of Chandy.