The deceased were a man aged about 42 and a woman aged around 32, according to the Jhalakathi fire service and civil defence.
Both the bodies were partially burned, said Shafique.
Coast Guard members and fire-fighters continued their search operation in the river for the sixth day in a row.
The police control room set up at the launch terminal provided information about 41 missing passengers, said Md Salauddin, a sub-inspector at Jhalakathi Sadar police station on Tuesday.
Meanwhile, an FIR was lodged at Jhalakathi police station on Monday night, following a complaint from the victims' side, accusing eight people, including launch co-owner Hamjalal Sheikh, for the tragedy.
Monir Hossain, a resident of Dhaka’s Bakhsnagar area, had filed the complaint as four of his family members -- Taslima Akter, 30, Sumaia Aktar Mim, 12, Suborna Aktar Tania, 8, and Zunayed Islam Bayezid -- still remained missing.
On Monday, the Rapid Action Battalion (RAB) arrested owner Hamjalal in connection with the deadly fire on board the launch, MV Avijan-10.
His arrest followed the Dhaka marine court’s warrants for the arrest of four owners and four staffers of the launch in a case filed by the department of shipping.
The accused are four owners of ‘Messers Al Araf and Company’, the firm operating the launch -- Md Hamjalal Sheikh, Md Shamim Ahmed, Md Rasel Ahmed, and Ferdous Hasan Rabby, -- and master in-charge of Avijan-10 Md Riaz Sikder, driver in-charge Masum Billah, second master Khalilur Rahman, and second driver Abul Kalam.
The blaze broke out around 3:00am on Friday on the Barguna-bound launch carrying some 800 passengers from Dhaka and it engulfed the entire vessel within 10 minutes.
The death toll from the fire accident climbed to 42 on Monday morning. Besides, over 70 people suffered injuries, and many of them are currently undergoing treatment at different hospitals.