The PSNI is to be given additional powers to legally enforce the Executive's stay-at-home message between 8pm and 6am, Health Minister Robin Swann said yesterday.
Health officials initially said it was an order, not a law.
Mr Swann said the PSNI would be given additional powers to enforce it after he made a request to the Executive, which was supported, to ensure people abided by the new rules for the Boxing Day lockdown.
The Health Minister added: "The regulations published tonight will see that go into (law).
"The Executive agreed to that yesterday and it is being worked through by the departmental solicitors' office to ensure it is legally enforceable.
"From 8pm to 6am that week, the police will have additional powers to enforce things."
Separately, terms of guidance issued by Stormont have stipulated that anyone returning to Northern Ireland for the festive season should self-isolate on Christmas Day.
The advice, published by the Executive, comes after ministers agreed earlier this week to recommend against any non-essential travel between Northern Ireland and both Great Britain and the Irish Republic.
The Executive also agreed to advise anyone arriving in Northern Ireland who is staying for more than 24 hours to self-isolate for 10 days.
It applies to anyone who has arrived since December 22.
People who intend to leave before 10 days elapse are free to do so.
The guidance confirms that people who regularly cross the Irish border for essential reasons, such as going to work, do not need to self-isolate.
New regulations came into force on Wednesday that gave legal footing to the Executive's decision to reduce the five-day period of Christmas relaxations on household gatherings to just one day between December 23 and December 27.
Local Covid-19 rates remain high, with another 21 deaths and 787 new cases confirmed on Wednesday alone.
Northern Ireland will enter a six-week lockdown on Boxing Day. The first week of the measures will be the toughest so far imposed.
The new guidance on travel was introduced after a Sinn Fein bid to ban travel between Northern Ireland and Great Britain was voted down by the Executive.
Separately, Leo Varadkar announced that there would be a Garda presence on the Republic's border with Northern Ireland from Boxing Day.
It is part of a range of measures introduced to ensure that travel restrictions are followed when the Republic enters lockdown again.
From Christmas Eve the country will begin moving to level five, the highest level of its Covid response, with some adjustments, such as allowing shops to remain open.
Restaurants and pubs will have to close at 3pm on December 24.
Close-contact services such as hairdressers and beauty salons will also close from Christmas Eve.
Inter-county travel will be prohibited after December 26.
Mr Varadkar previously raised the possibility that the lockdown could last until the spring.
Elsewhere in the Republic, government ministers are restricting their movements after a Cabinet member tested positive for Covid-19.
Agriculture Minister Charlie McConalogue received a positive result on Wednesday.