Universal has made 134 exclusive albums available for download on as part of its commitment to let music lovers buy rare material as digital downloads.
The initial batch of digital-download exclusives include The Walker Brothers' 'Live In Japan', three albums by the Comsat Angels, Bill Fay's eponymous album and UK blues band Nine Below Zero, among others.
A further 500 exclusive download albums are scheduled to be launched on the store in the coming six months. Future exclusives will also include never-before-released gems from the Trojan, Fiction and Decca archives.
Alongside download exclusives, the site features catalogue albums from a variety of artists, including Joni Mitchell, Scott Walker, Marianne Faithfull and The White Noise.
Other labels represented on the site range from Prestige, Verve and Impulse to A&M, Motown, Stax and Vertigo.
Downloaded tracks will work on any MP3-compatible fixed or portable device, including iPods, MP3 players and mobile phones.
The site features a "smart search" function, which allows users to browse by any combination of genre, decade and label. There are 38 genres and sub-genres ranging from progressive rock, electronica and dub, to jazz fusion, world, and spokenword.
Azi Eftekhari, head of digital and media for Universal Music Catalogue, said: "We wanted Lost Tunes to replicate the experience of going to a favourite local record shop where browsing and discovering music is a real pleasure and an adventure. We only include music that we love."
International versions of the Lost Tunes site will launch in the coming months.