Investigations into alleged abuses of MPs' expenses will be carried out in secret, under new proposals from the Commons watchdog.

The Independent Parliamentary Standards Authority's (Ipsa) compliance officer is also planning to bar the public from hearings.

The moves put out for consultation are likely to lead to accusations that the regime is less transparent than the one it replaced in 2010 - when the identities of those under investigation were routinely confirmed.

It also amounts to a second U-turn on the issue. Initially Ipsa's rules indicated that the names of MPs under investigation should be released when probes were launched, but the body's compliance officer Luke March then refused to do so on the basis it was "unfair".

He subsequently resigned and a consultation in 2011 concluded that the identities should indeed be made public during formal investigations rather than afterwards.

As a result, ongoing investigations are currently declared on the watchdog's website.

However, the latest consultation launched by compliance officer Peter Davis insists that the "public interest in transparency must be balanced with operational needs and fairness".

"On balance, we believe that the operational and reputational damage to MPs which could be caused by the publication of allegations in advance of a substantive investigation outweighs the benefits of release," it states.

"The compliance officer is likely to find discussions with MPs, staff and others more instructive and the evidence of a better quality when the discussions take place without the public scrutiny that accompanies press investigation.

"For this reason we plan now to amend the procedures so that the compliance officer is required to publicise the findings of all investigations as soon as practicable after its conclusion.

"This will follow the practice of the majority of bodies regulating professionals and ensure that the public receives full information on the allegation and the investigation together."

Previously, the compliance officer was obliged to "take reasonable steps" to allow members of the public to attend formal hearings into alleged wrongdoing by an MP.

But the consultation states: "To date, no MP has requested a public hearing. The compliance officer believes that this is because any MP is likely to judge that the benefits of the hearing would be outweighed by the possible publication of the details of the case."

It adds: "We now believe that the potential loss of the opportunity to gather further evidence through a hearing is unacceptable. Consequently, we propose to remove the reference to public attendance at the hearing."

The compliance officer has not carried out any full-blown investigations since ruling in July last year that Tory Nadine Dorries should repay £3,000 in travel expenses, despite not having "deliberately attempted to profit".

The proposed changes come after Ipsa disclosed that the bill for MPs' business and personal expenses rose by £5 million to hit £103 million last year.

It has also emerged that the watchdog will stop publishing itemised details of stationery claims to avoid embarrassing MPs.

Former Cabinet minister Ken Clarke has been mocked for claiming for an 11p ruler, while David Cameron was reimbursed 8p for a box of clips.

In a letter to the Speaker's Committee for Ipsa over the summer, the watchdog's new chief executive Marcial Boo hit out at "trivialisation in tabloid headlines".

"In our bi-montly publication of data about MPs' costs, we will now aggregate these items of stationery purchased from Banner, the direct payment supplier, in the same batch so that we will have a category of expenditure labelled 'invoice for stationery from Banner' rather than publishing individual lines for staples, pens and rulers," he wrote.

TaxPayers' Alliance spokesman John O'Connell called on Ipsa to rethink the plans.

"Yet again, Ipsa has demonstrated itself to be thoroughly out of touch with the public.

"Transparency must be the watchword and if it insists on keeping this probe secret it will undermine the whole point of setting up the organisation. It must rethink these proposals or taxpayers will deem Ipsa totally unfit for purpose."