Six Japanese ports have been damaged by the powerful tsunami that hit Japan last week.
The severely damaged ports include Hachinohe, Sendai, Onahama, Ishinomaki and Onahama, which are not expected to return to operation for months, according to Reuters.
The ports were medium-sized facilities that handled mostly containers, as well as fuel products and dry bulk goods.
Tokyo and all ports south of the Japanese capital have resumed operations.
The tsunami has also destroyed dozens of vessels, including three Kawasaki Kisen Kaisha panamax ships.
The closure of the ports is expected to cost Japan more than $3.4bn in lost seaborne trade each day.
Maritime trade in Japan totalled $1.5trn last year.