Government staff have been sending out data discs along with the password in the same package, it has been reported.
An email circulated by one of the Department for Work and Pensions' security advisers has reprimanded staff for sending packages that contained both password-protected discs containing sensitive information along with the password.
Despite high-profile data loss scandals over the past year, the email, leaked to blog Dizzy Thinks, said: "I have been advised of instances where password protected data has been sent out with the password being sent separately as detailed in Security Notice 02/07. However, once the data and the separate password are received, staff are then forwarding the data and password on together. This defeats the purpose of the security measure entirely.
"Could I ask you to remind staff of the heightened security surrounding data transfer and ensure that data and passwords are sent separately."
Instructions issued to civil servants last December made it clear that passwords should always be sent separately from sensitive information, whether it was being transported by courier or electronically.
Last November HM Revenue & Customs lost two discs containing 25 million child benefit records in the post.
In the six months since, Information Commissioner Richard Thomas has been notified of 94 data breaches, more than 60 of which where commited by Government or other public sector bodies.