Ms Park, who was heckled on Thursday when she met relatives of missing passengers, claimed it was increasingly clear Captain Lee Joon-Seok had unnecessarily delayed the evacuation as the capsized Sewol started sinking.
Ms Park told a Cabinet meeting: "The actions of the captain and some crew members were utterly incomprehensible, unacceptable and tantamount to murder."Not only my heart, but the hearts of all South Koreans have been broken and filled with shock and anger."
Families clash with South Korean police
She criticised 69-year-old Lee for "deserting" the passengers by "escaping first", adding: "This is utterly unimaginable, legally and ethically."
She added that all parties to the disaster, the owners, safety inspectors and crew would be investigated, and all those responsible would be held "criminally accountable".
Lee was arrested on Saturday along with a helmsman and the ship's relatively inexperienced third officer, who was in charge of the bridge when disaster struck.
Captain Lee was rescued from the sinking vessel
Lee was charged with negligence and failing to secure the safety of the passengers, most of them children travelling to the resort island of Jeju on a school trip.
Senior prosecutor Ahn Sang-don has said four more crew members - two first mates, one second mate and a chief engineer - have been detained on allegations of failing to protect passengers and abandoning ship.
Lee and the crew, most of whom escaped the ferry, have faced criticism for delaying the order to abandon ship - a possibly fatal error of judgement before the vessel fully submerged on Wednesday with 476 people on board.
More than 60 bodies have now been recovered
Meanwhile, divers have recovered more than 60 bodies. Around 240 people are still missing.
A government spokesman said they were putting into place measures to make it easier for families to collect the bodies of their loved ones.
He also said additional funding for the search and recovery operation would be prepared if needed.
A relative sits with others inside a gymnasium used as a gathering point for family members of missing passengers aboard the sunken South Korean ferry 'Sewol'.
