Royal Mail is to put on extra deliveries in NI to cope with the back-log caused by the severe weather.
Up to 14,000 extra evening delivery rounds are planned for Northern Ireland and the rest of the UK on Monday, Tuesday, Wednesday and Thursday.
A spokesman said the move followed a £20m investment to deal with the most severe December in almost 30 years.
Some people now have a second chance to receive items missed in an earlier delivery.
Around 2m UK homes are expected to receive an evening delivery in the coming week.
Royal Mail managing director Mark Highson, said: "The authorities are doing all they can to keep major roads clear but major routes, together with rail and air services across the UK, have been significantly impacted by heavy snowfalls in the last few days.
"This disruption has had an impact on Royal Mail, along with many other delivery providers.
"Royal Mail remains committed to delivering on behalf of its customers and that is why these extra deliveries have been put in place."