"I am ready to go to his (Naqvi's) place or he can come to mine and have a discussion and give proof. If he is right, I am ready to be hanged...," he said, and claimed that Naqvi may have considered Ali a "threat" to his position in the party.
He was addressing a press conference a day after BJP annulled his membership within 24 hours of his induction following intense opposition from within and the RSS. Naqvi had attacked Ali as "a friend of terrorist Yasin Bhatkal" and strongly opposed his entry into the party, terming it a "mistake" that needed to be rectified.
Ali said that the allegations levelled against him were completely "baseless".
He and his family have been affected by it and Naqvi must apologise or prove his allegations, the leader said.
Ali's wife, who was also present during the press conference, threatened to sit on a dharna in front of Naqvi's house if the BJP leader did not apologise.
"I want an apology letter from Naqvi within 24 hours stating the reasons behind his statement. Or else give us proof about his allegations," Ali's wife said.
"After 24 hours, if he fails to do so...I will sit alone on a dharna in front of his house. If I have to become a martyr (shahid) for truth, I will become one there (Naqvi's house) only," she said.
Ali, who had on Saturday threatened to file defamation case against Naqvi, on Sunday said, "It has been 56 hours since I challenged Naqvi to have a debate or give proof of his allegations. There has been no reply.
"We have prepared the notice and it will be served to him through my lawyer. I have challenged him and say this today as well.
"I know that foundation of lies is always weak... I have been a Rajya Sabha member for six years, I was in JD-U. During that time nobody said anything. But the day I joined BJP, he (Naqvi) perhaps thought that people like me who are connected to ground reality would become a threat to him," Ali said.
Infighting forces BJP to annul Sabir Ali's membership
Storm over Sabir Ali leaves RSS, Modi divided
JD-U and Indian Mujahideen: A murky relationship?
When a feminist turns right
Prove my links to Bhatkal, dares Sabir Ali