Located at 72 Carfin Road, the service which launches at 1pm on Saturday, March 5, will be provided from three counter positions.
These include two secure fortress positions and a combi-counter, where the Post Office terminal will sit alongside the retail till.
The branch will be open for an extra 26 hours a week, from 9am-5.30pm on Monday-Saturday, with selected Post Office products and services available from the retail counter during shop opening hours, which are 8am-10pm on Monday-Saturday.
Newarthill Post Office will close at 5.30pm on Friday, March 4, for the refurbishment to take place, and anyone needing postal services the next morning can use any convenient Post Office including New Stevenston and Cleland.
Area manager Damian Mulholland said: “We are making it easier for customers to get their cash, send and collect their mail and do their banking because we know how important these services are to local residents.
“We are confident that this vibrant new-style Post Office at the heart of the local community will meet customer needs.
“This modernisation is part of a major investment programme, the largest in the history of the Post Office, and will secure services for the future.”