While the party leadership is reported to have accepted his joining, his formal joining will take place later in Bhubaneshwar.
The 72-year-old tribal leader from Odisha, who quit the Congress on May 30, said he decided to join the BJP as he liked its political strategy.
"I have decided to join the BJP, but I will join formally soon. It will be decided by the state unit soon. I had met the Amit Shah today and made my plea which has been accepted by the party leadership," Gamang said after an hour-long meeting with Shah.
"BJP is a national party and now it has proved as an alternative to Congress. The way they are having their strategy in Indian democracy, I think this new concept of political strategy...I like it as it is not only to be in power but also to serve people," he said.
Union Ministers Jual Oram, also a tribal leader from Odisha, and Dharmendra Pradhan, besides party's secretary Arun Singh were also present during the meeting.