A hacker has managed to alter the internet track listings of a New Zealand Symphony Orchestra (NZSO) CD to show details of sex acts.

According to the Dominion newspaper, users playing the CD via a Real One player and looking for album information on an internet database are instead given a description of a type of movement they were not expecting.

Orchestra members, who were alerted to the problem soon after the promotional CD was sent out to 8,000 people, were said to be "horrified".

A spokeswoman said that the orchestra contacted the CD's producer, Wellington-based Amstore, which traced the problem to an American media player database known as Gracenote.com.

The person responsible had used an internet media player to read the CD, and had then made the changes and had saved them on the Gracenote database. Anyone using a media player connected to that database then saw the X-rated version.

Gracenote said that it has now removed the hacked listings.