SAN FRANCISCO (AFP) - Google on Tuesday said that it has bought Songza, a free online streaming music service that recommends tunes based on what people might be in the mood to hear.

Financial terms of the deal were not disclosed, but unconfirmed online reports valued the deal at around US$15 million (S$18.7 million).

"We're thrilled to announce that we're becoming part of Google," Songza said on its website.

"We can't think of a better company to join in our quest to provide the perfect soundtrack for everything you do." Songza added that no immediate changes were planned for the free service, other than making it faster, smarter, and "even more fun to use." Songza suggests playlists based on where people are and what they are doing, such as starting a day at home; grinding away at an office, or out exercising.

It has applications tailored for mobile devices powered by Apple or Google-backed Android software.

Songza features that have resonated with users will be woven into Google Play Music and YouTube where possible, the California-based technology titan said in a post at its Google+ social network.

"They've built a great service which uses contextual expert-curated playlists to give you the right music at the right time," Google said.

New York-based Songza has been likened to Pandora, which has a leading ad-supported streaming music model.

Google, Amazon and Apple have music services that compete in a market where Pandora and Spotify have found success.

Apple in May bought Beats Music and Beats Electronics in a deal worth US$3 billion to bolster its position in the hotly contested online music sector.

The move is expected to help the US tech giant - a pioneer in digital music with its wildly popular iTunes platform - ramp up its efforts to counter the successful models of streaming services like Pandora, Spotify and others.