He said 98 per cent of his party's voters would be stepping out to cast their ballots. "My lead will increase," Mr Parrikar said.
When asked about his chances of winning the Panaji assembly seat for the sixth time, he said, "I can't see any opposition."
Asked about putting in more than usual effort in the by-poll campaign, than he and the BJP had in the past, Mr Parrikar replied: "Shouldn't one campaign?"
"There were general elections when I would campaign all over Goa. Now we are campaigning only here," Mr Parrikar said, after casting his vote at the Masson de Amorim polling booth.
Speaking to reporters here, former state RSS chief Subhash Velingkar, who is the mentor of the Goa Suraksha Manch said that the Rashtriya Swayamsevak Sangh volunteers would not support Mr Parrikar.
"RSS workers will not vote for him and our Anand Shirodkar will win this election, with a small margin," Mr Velingkar said.