In view of sharply rising coronavirus infections in Portugal, the government has brought forward planned restrictions on public life that were originally due to take effect from December 31.
From December 25, working from home will be mandatory wherever possible, and nightclubs and bars will have to close, Prime Minister Antonio Costa announced on Tuesday.
Costa said the steps were necessary because of the risk that the situation will worsen due to the highly contagious Omicron variant.
The need to provide proof of having been tested will be extended to hotels and other public venues.
School lessons are to resume on 10 January, later than the usual return to school after the New Year.
Despite a high vaccination rate of around 90 per cent of the population, the seven-day incidence of coronavirus infection in Portugal has risen to over 300.