Households in Belfast City Council - along with parts of Co Antrim and Lisburn - will not be allowed to mix indoors under the new coronavirus restrictions.
The measures were announced on Thursday by the First Minister, Arlene Foster and the Deputy First Minister, Michelle O'Neill at their first joint press conference in over two months.
Under the new rules, which will come into force some time next week, there will be "no mixing of households in private dwellings".
Once in effect, the rules will be in place for two weeks before they will be reviewed.
However, with traditional pubs - ones which do not serve food - set to reopen in less than two weeks, the Executive risks a public backlash, given households - which have been ordered to not meet indoors - can be allowed to gather in pubs and restaurants.
The Executive Office admitted that the new rules would create confusion for households on the outskirts of the identified areas but stressed that it is "unavoidable".
The rules apply to Ballymena town and BT43, Belfast City Council, and postal areas BT28 and BT29, which is located in Lisburn, and has been estimated to affect at least 700,000 residents.
No more than six people from two households can meet in gardens, although there are exemptions for those with child care and other caring responsibilities.
Other exemptions include social bubbles with one other household, essential maintenance, supported living arrangements; visits required for legal or medical purposes; or marriage or civil partnerships where one partner is terminally ill.
The household clampdown follows a series of arrests for a range of coronavirus-related offences in the Holyland district near Queen's University, Belfast over recent days.
The intervention comes as another 78 people tested positive with Covid-19 yesterday in Northern Ireland.
One further death was also reported, bringing the total to 568.
Mrs Foster said: "There are areas where the spread is of particular concern, where cases are double or treble the average rate for the province."
Mrs O'Neill stressed she believed the new restrictions were "proportionate and necessary" in the context of the ongoing Covid-19 crisis.
The measures have been welcomed by the British Medical Association NI council, with its chairman, Dr Tom Black declaring the Executive could not "run the risk" of hospital admissions rising.
He also warned others living outside the restricted postcodes that they were not invincible to the threat, urging the affected households to not wait for the rules to come into official effect, but to adhere to them immediately.
Meanwhile, 'wet' bars - licensed premises which do not serve food have been given an indicative date to reopen on September 21.
Soft play areas can welcome back customers a week earlier on September 14.
Addressing claims the new rules create apparent contradictions in the mind of the public, Mrs Foster said the spread of Covid-19 was happening in households.
Insisting that the "villain is in our households" and not in businesses, she added: "It is a grave situation but we also need to ensure that our economy continues to flourish."
The DUP leader also emphasised that it was necessary to target households as current Covid-19 cases figures increasingly revealed the virus is affecting more older people.
Earlier this week particular concern had been expressed about parts of Belfast, and the impact of house parties as students return to university.
Police revealed five people were arrested in the Holyland and a total of 10 community resolution notices and eight fixed-penalty notices, which carry a £60 fine, were issued.
A new Ministerial-led group will be set up to consider compliance and enforcement of the regulations, the Executive Office has revealed, adding it is also working to "provide any necessary clarity" for households on the boundaries of targeted areas.
"In the interim, anyone in any doubt as to whether they are covered by the restrictions is asked to follow them," the statement added.
On the Belfast Telegraph's website on Thursday morning I wrote; 'I detect a touch of choreography in the O'Neill/McDonald/Foster statements in the past few hours (and) it sounds to me like a door is being nudged open.'