MPs have agreed that the prime minister's adviser on ministers' interests should have the power to instigate his own investigations.
Conservative MP and chairman of the public administration select committee Bernard Jenkin argued that the current regime, under which the prime minister decides whether any of his or her ministerial colleagues warrant investigation, should end.
It was feeding "public suspicion that ministerial conduct can be protected from proper investigations", he explained.
On 17 July 2012, MPs debated a motion put forward by Mr Jenkin calling on the government to make the change, before approving it without a vote, as recommended in a recent
by the committee.
Mr Jenkin said: "How can the prime minister be objective, any prime minister be objective, or perhaps more importantly be seen to be objective, when he has to make judgements about close colleagues that could have far-reaching politician consequences?"
He added: "The problem of the present system is this: as soon as the question of a serious potential breach of the code and a possible referral to the prime minister's adviser, the Prime Minister is damned if he does and damned if he doesn't.
"Referral is seen either as condemnation of the minister's conduct or an attempt to protect the minister from a full investigation."
Cabinet Office minister Nick Hurd indicated that the government disagreed with the committee.
"It is, we suggest, to misunderstand the intended role of the independent adviser to suggest he or she should be able to instigate their own investigations," he said.
The prime minister was the "ultimate judge" of the standards expected of ministers and it was up to him whether any investigations needed to be carried out, Mr Hurd contended.
Shadow Cabinet Office minister Gareth Thomas said Labour was "open minded" on whether the change was needed.
The report from 14 March this year said: "The independent adviser should be empowered to instigate his own investigations.
"The prime minister could do this on his own initiative, without any need for legislation, but placing the post on a statutory footing would be preferable."
The investigation by the Public Administration Committee focused on the circumstances that led to the resignation of former Defence Secretary Liam Fox last year.
The committee said Sir Philip Mawer seemed to have been "cut out of the loop" during the inquiry into Mr Fox's links with his adviser Adam Werritty.
A probe was conducted instead by the then Cabinet Secretary Sir Gus O'Donnell.
MPs said this reflected a reluctance to refer "difficult cases" to the adviser.
Sir Philip has since retired and been succeeded by Sir Alex Allan, a former chairman of the Joint Intelligence Committee.