Royalty rates for music played via internet radio services could be set to triple, if the Recording Industry Association of America (RIAA) gets its way.

The US Copyright Royalty Board (CRB) has endorsed a plan by the RIAA to retroactively raise the fees Internet radio broadcasters must pay to stream music.

Internet radio broadcasters, including the likes of Pandora, may be threatened by the fee hikes. Last.FM would be exempt from the ruling as it is based in London.

The new rates will require webcasters to pay for each song which they stream to users. The cost of streaming one song is set to rise each year, from $0.0008 to $0.0019 in 2010.

This may not sound much, but for heavy users the cost can rise to $0.0128 per listener per hour, which is more than many internet radio services make from subscriptions or advertising.