Transportation minister Kazuyoshi Akaba says Japan will tighten border controls and limit the number of entrants to up to 2,000 per day to guard against the more contagious variants of the coronavirus.
Japan has confirmed 345 cases of the more contagious new variants, mostly the kind first found in Britain, the health ministry said.
The health authorities have found the cases of the new variants to have quadrupled over the past month. They said the cases have been found in about half of Japan's 47 prefectures but need to be closely watched and precautions should be increased.
Tokyo and its three neighbouring prefectures are under a non-binding state of emergency since Jan. 7. The measure, which was to end on March 7 in those areas, has been extended for two weeks as the infections have not slowed enough.
Japan had about 444,300 cases and 8,451 deaths as of Thursday, the health ministry said.