Proposals to extend the ARB's Professional Conduct Committee (PCC) will come under scrutiny at a special statutory committee hearing in the House of Commons later this year.
Liberal Democrat MP Evan Harris has successfully launched a 'Praying Motion' demanding increases to PCC membership be properly debated before becoming law.
The motion means that the changes have to become the subject of the committee debate before they enter the statute books.
Harris, the member for Oxford West and Abingdon, was recruited by ARB rebel Ian Salisbury to use his parliamentary clout to scrutinise the changes.
Harris has since persuaded the Liberal Democrat Whips' office to support the motion, recruiting Liberal leader Charles Kennedy and deputy leader Menzies Campbell to sign-up as well.
'I have been in contact with Ian Salisbury and he persuaded me that these changes need to be looked at a bit more closely, ' Harris told the AJ. 'We will get to scrutinise them seriously in the committee before they are introduced.
'It is unlikely we will get the government to drop the changes because it has such a huge majority, ' he added. 'But it is possible that our arguments might be so strong that they have a rethink.'