Jiang Zhao, general manager of the company which operated the Eastern Star, bowed in apology for the disaster during an interview with state media, saying the company would “fully” co-operate with the investigation.
Beijing has pledged there will be “no cover-up” in the investigation into the disaster.
Police have detained the captain and chief engineer for questioning as part of the investigation. An initial probe found the ship was not overloaded and had enough life vests on board.
The disaster is China’s worst shipping catastrophe in 70 years, and has now caused a higher toll than the sinking of a ferry in South Korea in April 2014 that killed 304 people, most of them children on a school trip.
More than 1,400 family members travelled to Jianli where the ship went down, with many expressing frustration at the lack of information given by the government.