Those joined BJD were late Sahu's wife Ritarani Sahu, his son Sumit Sahu and hundreds of their supporters at Bijepur, Patnaik told reporters.
3,000 Congress workers from Bijepur have also joined the party. This will strengthen the BJD, he said.
Ritarani Sahu said We joined the BJD today as per the desires of my late husband. I'll contest in the by-election.
Subal Sahu, a three time MLA from Bijepur, had died on August 22. "My father had started his career with the BJD. He had the wish of contesting in the 2019 Assembly polls from Bijepur constituency as a BJD candidate," said Sumit Sahu.
Sahu was elected to the Odisha Legislative Assembly thrice (2004, 2009, 2014) from Bijepur constituency. He had defeated top BJD leader Prasanna Acharya in 2014 Assembly polls.