Preliminary investigations revealed that the fire might have been started by a group of five inmates who set several blankets ablaze at the maximum correctional facility on the outskirts of Harare, according to the Zimbabwe Broadcasting Corporation (ZBC). The fire brigade was called in to put out the fire, which had spread to a staircase.
Prison officers reportedly combed the prison in the wake of the blaze.
According to unconfirmed reports the fire was part of an attempted jail-break.
Sources reportedly said there had been a number of arrests.
It was believed that none of the prisoners escaped from the jail.
Prison officers said they heard some of the inmates urging their colleagues not to eat their meal, protesting that the relish was not good enough, ZBC reported.
Investigations were still underway.