Spotify has issued a warning that it has suffered a security breach that could mean user's passwords have been compromised.

The music streaming service has emailed its users to notify them that a group has "managed to compromise" the site's protocols and had gained access to information that could allow testing of large numbers of passwords, in order to find the right one.

The site warns: "Along with passwords, registration information such as your email address, birth date, gender, postal code and billing receipt details were potentially exposed".

However, credit card numbers are not stored by the site and are therefore not said to be at risk.

Spotify warns: "If you have an account that was created on or before December 19th 2008, we strongly suggest that you change your password and strongly encourage you to change your passwords for any other services where you use the same password".

Spotify, which recently hit the million members milestone, apologies for the breach:

"We are really sorry about this and hope you accept our apologies. We're doubling our efforts to keep the systems secure in order to prevent anything like this from happening again".