Bloomberg cites sources close to the company claiming that the music streaming giant has already informed content partners of its plans.
An online radio add-on could grant Spotify subscribers access to music yet to be licensed by the Swedish firm, such as material by Coldplay, The Beatles, Metallica and Adele.
The application is expected to take its cues from Pandora, serving users with a playlist of music by similar artists to ones that they have specified. Spotify would likely have to strike up a royalties agreement with the Performing Right Society to launch such a service in the UK.
The report speculates that Spotify intends to use the new online radio app as further incentive to convince users to sign up for its top premium package at £9.99 per month.
Earlier this week, it was reported that Microsoft is planning to unveil a Spotify-esque service for its Xbox 360 console at this summer's E3 2012.