The Sri Lankan, staying on the sixth floor, received 90 per cent burns when the first blast went off at about 9:30pm Sunday, said police chief Farid Ahmed.
Two more loud explosions within two hours rocked the two-star hotel as police, explosive experts, firemen and journalists arrived, injuring at least another 35 people, deputy police commissioner Mazharul Islam said.
"At least 18 people including 10 police officers were admitted to hospitals with burn injuries and wounds caused by flying glass. Others suffered minor injuries," he said.
Police and firemen rescued more than a dozen people including a Singaporean trapped in the top floors of the 12-storey building near Dhaka's commercial district.
Fire gutted several floors of the hotel, which had some internal walls knocked out by the force of the blasts.
It was not clear what caused the explosions but police said leaking gas and electrical short circuits could be to blame.
"Explosive experts of the Rapid Action Battalion have not found any explosives in the scene. They suspect gas leakage from the air conditioners or in the pipeline and short circuit for the explosions," he said.
No arrests have been made, Ahmed said.