The MV Barima was traveling from the capital Georgetown to Port Kaituma in Guyana's inland Essequibo region when it flipped over on Saturday night.
A desperate search for survivors began early Sunday, with 76 people rescued so far, according to Phillips, after the government previously said 77 had been located alive.
The prime minister on Tuesday revised the death toll for the second time in one day, raising it from 41 to 53.
"A total of 53 bodies have been recovered," Phillips told a press conference.
"We've recorded 76 persons that were rescued as of 6 p.m. (2200GMT) today," he said.
