Nadine Ramaroson, Madagascar’s minister for population and social affairs, drowned after “a wave capsized [her] boat near the Soanierana-Ivongo channel,” General Richard Ravalomanana, gendarmerie district commander in Antananarivo, said.
“There were 11 people on board, four were killed,” he added.
The general said that seven others were killed by an explosion during the rescue operation.
The minister was returning from a cultural festival on the island of Saint Marie, 40km from the Madagascar mainland.
Ramaroson is the niece of Alain Ramaroson, a key figure in Madagascar’s current regime.
Madagascar has been in political turmoil since current strongman Andry Rajoelin ousted former president Marc Ravalomanana in a military-backed coup.
The impoverished Indian Ocean island nation has been gripped by political tensions since the ex-president’s ousting.