NFSP general secretary George Thomson said that the Post Office needed to remind customers of the services it offers communities.
"We welcome the campaign as it brings the Post Office back into the minds of customers," he said. "The adverts will hopefully get people back who have stopped using Post Office services over the past couple of years."
Despite subpostmasters' salaries being slashed earlier this year, Thomson said that "while more pay would be welcome, it is important to invest in the network by promoting it to the public and reminding them to use their local post office and generate more business for us".
The new campaign was rolled out at the start of July and features TV advertising running across satellite and terrestrial networks. Using the tagline 'there is more that unites us than divides us', the campaign takes the theme that the network provides a hub for the community.
Post Office marketing director Gary Hockey-Morley said the adverts aimed to build on the network's heritage as a community brand.