Dublin will be moved to level three restrictions from midnight while indoor dining is also to be banned for three weeks.
Restaurants and pubs can continue to do takeaway and have a maximum of 15 customers outdoors.
People should not leave or enter Dublin unless it's for work, education or other essential business.
Visits to nursing homes have been suspended while indoor gatherings have been banned.
Weddings planned for this weekend can go ahead with 50 guests but will be reduced to 25 after that.
Confirmations, communions and other religious services are to move online or be cancelled.
Taoiseach Michael Martin says Dublin could return to the worst days of the crisis unless action is taken.
Tánaiste and Enterprise Minister Leo Varadkar says special financial support will be available for Dublin businesses.