But he told families they should plan for Christmas "as normal".
The Cabinet Minister said on Sunday the situation is "nowhere near" the need to reintroduce social distancing rules and work from home guidance, despite a raft of precautionary measures being reintroduced to tackle the concerning strain.
Passengers arriving to the UK have been told that from 4am on Tuesday they will have to take a PCR test for Covid-19, with the expectation they will have to self-isolate until they test negative.
All contacts with a suspected case of Omicron will have to isolate for 10 days, regardless of their vaccination status, amid concerns existing jabs will be less effective against the strain that is believed to spread rapidly.
Details of the plans were incomplete when announced by Boris Johnson after two cases of the variant were confirmed in England on Saturday, but Mr Javid said the "face mask rules are planned to come in on Tuesday" to bring the nation back closer into line with Scotland, Wales and Northern Ireland.
He said it "would be irresponsible to make guarantees" during the ever-changing pandemic, but told Sky's Trevor Phillips on Sunday: "I think people should continue with their plans as normal for Christmas, I think it's going to be a great Christmas."
With the Government stopping short of introducing its Plan B to tackle Covid-19 this winter, Mr Javid downplayed there being a need to reintroduce social distancing rules or work from home guidance.
"We know now those types of measures do carry a very heavy price, both economically, socially, in terms of non-Covid health outcomes such as impact on mental health," he told Sky.
"So if one was to make decisions like that they would have to be done very, very carefully and we're not there yet, we're nowhere near that."