The giant wave hit the town of Ofunato in Iwate prefecture following a magnitude 9 earthquake, the Kyodo News agency reported, citing the Port and Airport Research Institute.
Police said the confirmed death toll in the earthquake and tsunami disasters stood at 9,700. Another 16,501 people were reported missing.
A magnitude-4.9 aftershock hit the Kanto region surrounding Tokyo at 8.56 a.m.
Construction work on temporary housing began in Kamaishi city in Iwate prefecture. Building work was due to begin on similar housing in Ofunato and Miyako, also in Iwate, Friday.
The Tohoku Expressway, a major road linking Tokyo and the quake- and tsunami-hit areas in the northeast of the country, reopened to all traffic Thursday. It was previously limited to emergency vehicles and those transporting relief goods and workers.