Children are increasingly swapping music via mobile phones, often without realising they can be breaking the law.
Mobile phone use among children is growing
A survey of almost 1,500 eight to 13-year-olds found almost a third shared music via their mobiles.
Children are using the built-in Bluetooth wireless feature of many phones to swap music - but without the consent of copyright holders.
Robin Hart of Intuitive Media, which conducted the survey, said the problem was a worry for the music industry.
Almost a half (45%) of children who said they did not swap music via their phones said they would like to.
The survey did not breakdown what percentage of music shared had rights attached to it or was free to exchange.
Mr Hart, co-founder of Intuitive Media, said: "Music sharing on the internet was identified by the industry as one of the biggest threats they've faced in recent years and this research shows that mobile has got the potential to exacerbate those problems.
"The children are not aware they are doing anything illegal."
He said the industry should not take legal steps to stop the practice at this stage.
"Children are doing this quite innocently. We don't need to criminalise them," he said.
The music industry has said it was "concerned" by the findings.
It has complained for many years that it is losing billions of pounds to music piracy via the net, although critics say the trend of falling sales is more tied to changing patterns of consumption.
More than a million children in the UK under 10 years old - one in four - already have a mobile phone and newer models are commonly used as MP3 players to listen to digital music.
By 2007 the average age someone will receive their first mobile phone will be eight in Europe, according to the Wireless World Forum Youth Report 2005.
Justin Pearse, Mobile Editor of New Media Age, which co-commissioned the survey, said: "The music capabilities of mobile phones have really exploded in the last few months so this type of illegal music sharing was only to be expected.
"Nearly three quarters of kids are either already sharing music like this or want to be doing so."
Mr Pearse said he expected mobile music swapping to become a "truly mass market phenomenon in a matter of weeks or months" with the arrival of high-end phones this Christmas.
The music industry reacted with a wave of lawsuits when net song-swapping services like Napster took off in the 1990s.
It has since followed this up with lawsuits against individual users accused of hoarding and swapping music without permission from copyright holders.
Intuitive Media, which runs safe social networks for primary and secondary aged children in association with educational authorities, said the survey was carried out to get a better sense of how children used their phones.
"We were quite surprised by how young the kids were when getting phones," said Mr Hart, who runs GoldStarCafe.com and SuperClubsPlus.com.
He added: "53% of seven year olds on our sites own a mobile phone. It's very important to them and they use it a lot - half of the time phoning mates and half phoning family."
Mr Hart acknowledged that while the problem was a growing one it wasn't a "great problem yet" for the industry.
The threat of Napster and other sites was in the ability to deliver one copied song to hundreds of people almost simultaneously. Song swapping via mobile phones is currently one-to-one when using Bluetooth.
"This is a great opportunity for the industry. 26% of the children are buying things for their phone, costing at least £1 once a week,
"If the industry can offer cheap music downloads, make them easy to use and take advantage of Bluetooth spread, there are great opportunities.
"The industry will waste time and money trying to stop this. There's a viral thing happening here, and the music industry can take advantage of it."
Matt Phillips, communications manager for the BPI, which represents the UK music industry, said: "The illegal sharing of music is clearly a concern for the record industry.
He added: "While swapping songs via Bluetooth is a concern for the industry, it hasn't caused the same problems as illegal p2p filesharing as it's copying on a one-to-one, rather than one-to-millions basis.
"Ultimately the way to grow revenues with mobile will be to offer music fans what they want and encourage them to get their music legally."