Alphabet Inc's Google said on Thursday it is indefinitely pushing back its January return-to-office plan globally amid growing concerns over the Omicron variant of the coronavirus and some resistance to company-mandated vaccinations.

Google in August had said it would expect workers to come in about three days a week from Jan. 10 at the earliest, ending its voluntary work-from-home policy.  

On Thursday, Google executives told employees that the company would put off the deadline beyond that date. Insider first reported the news.

Google said the update was in line with its earlier guidance that a return to workplaces would begin no earlier than Jan. 10 and depend on local conditions.

Nearly 40% of U.S. employees have come into an office in recent weeks, Google said, with higher percentages in other parts of the world.

But CNBC reported last week that hundreds of employees have protested the company's vaccination mandate for those working on U.S. government contracts.

Google was one of the first companies to ask its employees to work from home during the pandemic. It has about 85 offices across nearly 60 countries.

Europe has so far recorded 79 cases of the Omicron variant, first detected in southern Africa last month, the European Union's public health agency said earlier on Thursday.  

(Reporting by Deborah Sophia in Bengaluru and Paresh Dave in Oakland, Calif.; Editing by Anil D'Silva and Richard Pullin) ((DeborahMary.Sophia@thomsonreuters.com;))