The Bairro Novo neighbourhood of Lobito, located on the Atlantic coast some 500 kilometres (300 miles) south of the capital Luanda, was worst affected by the downpours on the night from Wednesday to Thursday, with the water up to three metres deep in places, the agency added.
Thirty-five of the 62 dead were children, it said.
President Jose Eduardo dos Santos asked the provincial government to help the families affected by the tragedy, while offering his condolences to the relatives of the dead, a presidency statement said.
One person was already killed in a storm on Tuesday that also destroyed 137 houses and left more than 400 families homeless in Luanda, the local government said.