Presenting its fourth round of measures in two weeks, the government announced a ban on serving alcohol in bars and restaurants, a closing of gyms and swimming pools to most users, and stricter rules in schools, among other things.
"There is no doubt - the new variant changes the rules. That's why we need to act fast and we need to act again," Stoere told a news conference.
"For many this will feel like a lockdown, if not of society then of their lives and of their livelihoods."
Britain on Monday recorded the first publicly confirmed death globally from the swiftly spreading strain.
To speed up vaccination with booster doses, the government said the armed forces, as well as pharmacies, would assist in the inoculation campaign.
At the same time, quarantines would apply more widely, the government said.
Norway is setting record highs in terms of new COVID-19 infections and hospitalisations, partly due to the spread of Omicron, which is expected to become the dominant variant in the coming days.
"A lack of action now could lead to large negative consequences for society, not just for health services and municipalities," the Norwegian Institute of Public Health (FHI) said.
Unless effective measures were established, the nation of 5.4 million people risks having between 90,000 and 300,000 new COVID-19 cases on a daily basis from early January, the FHI added.
