UPDATE 2-Acting now on COVID will help avoid lockdown later, Britain's Javid says

* PM Johnson announced moved to 'Plan B' on Wednesday

* Omicron could lead to 1 million infections by month-end

* Javid says measures designed to have minimal impact on business (Adds details of Plan B measures, background)

By Alistair Smout and Guy Faulconbridge

LONDON, Dec 9 (Reuters) - Britain's decision to impose restrictions to slow the spread of the Omicron coronavirus variant will likely avoid the need to impose much tougher controls in the new year, Health Secretary Sajid Javid said on Thursday.

Prime Minister Boris Johnson imposed tougher COVID-19 restrictions in England on Wednesday, ordering people to work from home, wear masks in public places and use vaccine passes to slow the spread of the Omicron coronavirus variant.

Javid said the Omicron variant was spreading more swiftly than any other variant studied and could result in around 1 million infections across the United Kingdom by the end of the month if transmission continued at the current rate.

The government has acted in order to stop the National Health Service (NHS) coming under unsustainable pressure, Javid said.

"I hope that most people will understand that by taking some decisive action now, we can potentially avoid action later," Javid told Sky News.

Asked if tougher measures could be imposed in January, Javid said: "No. I hope not."

Javid said the measures would buy time to give more people booster shots, which he said would boost protection against severe disease even if Omicron was able to partially evade vaccines.

But businesses reacted with incredulity to a work from home order during one of the busiest trading periods of the year, in the run-up to Christmas.

Asked if there would be further support for firms who might lose money due to Plan B coming into force, Javid said it would be kept under review but the measures should not be too damaging.

"The measures we've taken under Plan B, although they have an impact, they're designed to have the minimal impact," he said.

Javid said there was no plan to impose mandatory COVID vaccination for the general population. (Reporting by Alistair Smout and Guy Faulconbridge)