More than 600 civil servants have been disciplined or sacked for accessing personal or sensitive tax data, the government has admitted.

Treasury minister Jane Kennedy said on Wednesday that HM Revenue and Customs (HMRC) had a "strict" policy banning staff from accessing customer records without a legitimate reason.

In a Commons written reply to Conservative home affairs spokesman James Brokenshire, she said the penalty in many cases was dismissal.

Figures provided by the Treasury show 238 people were disciplined or dismissed between April 2005, when HMRC was formed, and December 2005. A further 180 cases occurred in 2006 and 192 in 2007.

Kennedy wrote: "HMRC has a strict policy forbidding staff to access customer records unless they have a legitimate business need.

"Breaches of this policy are taken seriously and any breach will result in the commencement of disciplinary proceedings.

"Each case is treated on its merits but in many cases, the disciplinary penalty for breach is dismissal."

She said the figures represented less than one per cent of HMRC staff and showed the "strength of HMRC's internal disciplinary procedures".