"An explosion caused by an explosive device hit a civilian vehicle travelling along the main road in Al Khawkhah district, south of Hodeidah," the local military official said on condition of anonymity.
A family of four civilians died immediately in the roadside bombing that destroyed their vehicle, the source added.
A medical source at a local field hospital confirmed receiving the bodies of four victims and two injured women.
"The dead civilians were a man, his wife and two of his children, one of whom was a 10-day-old baby," the medical source said, also on condition of anonymity.
Yemen's government forces accused the Iran-backed Houthi rebels of being behind the roadside bombing.
As the main Yemeni port city along the coast of the Red Sea, Hodeidah is the key lifeline entry of most Yemen's commercial imports and humanitarian aid.
The Iran-allied Houthi rebels control much of Hodeidah while the Saudi-backed government troops have advanced on the southeastern districts of the strategic port city.