The Kanto region may experience a serious drought this summer, possibly triggering a raft of restrictions, due to an "unprecedented" shortage of water in lakes and reservoirs supplying the area, officials warned Tuesday.

Although the region expects decent rainfall over the next few days, hopes remain slim that it will significantly alter the dire forecast, they said.

Officials have already imposed a 10 percent restriction on water intake for six prefectures around the Tone River, while a 20 percent restriction is in place for cities drawing from the Watarase River.