More than 1 million songs can be downloaded in the MP3 format. Cardholders will be able to purchase bundles of songs, starting from 30 tracks for 5,500 Nectar points.
Until the end of October, a special offer will run allowing 20 songs to be downloaded for 3,000 points.
Nectar says that the launch is being supported through a marketing and PR campaign and the creation of a custom-branded web site accessible through the Nectar homepage.
Nectar also confirmed that it is to run a campaign featuring a major music star, details of which will be unveiled in the next few weeks.
Nectar marketing director John Sheekey said: “This is a first for a UK loyalty card and we’re excited to be leading the way in the ever popular world of online digital music.”
The loyalty programme is working with Hip Digital Media to run the music store.