Infections linked to people who arrived from the UK were reported in Spain, Switzerland, Sweden and France.
A couple found infected in Ontario, Canada, had no known travel history or high-risk contacts, officials say.
Japan is to ban most non-resident foreign nationals from entering the country for a month from Monday.
Since reporting infections in five passengers who had all arrived from the UK, the country has confirmed two more cases, one of which is said to have been domestically transmitted.
News of the new variant triggered travel restrictions around the world last week.
Meanwhile, several EU countries have started to vaccinate people against the virus ahead of a co-ordinated rollout across the whole bloc on Sunday.