Controversial plans to conduct secret inquiries into MPs' expenses have been criticised.

The Independent Parliamentary Standards Authority (Ipsa) said MPs and peers will no longer be named when investigations are launched, in the interests of fairness.

The Standards Committee and the independent Committee on Standards in Public Life (CSPL) have voiced concerns about the apparent lack of openness.

Compliance officer Peter Davis said the change would balance the "public interest in transparency" with "operational needs and fairness." He highlighted the "reputational damage" caused to MPs by naming them before investigations are complete.

The measure, put out for consultation in September, has come under fire for making the Ipsa regime less transparent than the one it replaced in 2010, when the identities of those under investigation were routinely confirmed.

The CSPL pointed out that the commissioner unhesitatingly named MPs they were investigating.

The Standards Committee's response said: "There is clearly a difficult balance between transparency and the fair and efficient conduct of investigations. We consider it is possible that the changes proposed in the consultation may tilt the balance too far from transparency.

"We invite Ipsa to consider whether the advantages of removing the assessment stage outweigh the transparency brought by the current system, in which names are released if it appears there may be grounds for investigation."