Japan's Prime Minister Fumio Kishida has said he wants to speed up the country's Covid-19 booster shot programme to one million shots a day by the end of the month, about double the current pace, according to public broadcaster NHK.

Kishida told a budget committee meeting that he has instructed ministers to work with local governments to speed up inoculations as much as possible, NHK said.

Nationwide infections surpassed 100,000 on Saturday for the first time. Most regions are now under infection control measures to try to blunt the spread of the Omicron coronavirus variant that has exploded among a population where less than five per cent have received vaccine booster shots.