APPC chair Robbie MacDuff told PRWeek that Tory threats to bring in tough new legislation had struck a chord with certain lobbyists outside of the APPC.
Shadow minister for the Cabinet Office Francis Maude declared last week that public affairs firms should publish all client lists and their full-time and part-time staff.
'If the industry fails to self-regulate, it should be prepared for legislation that will ensure greater accountability,' warned Maude.
Speaking this week, MacDuff said: 'I think Maude's comments have been noted by a significant group of lobbyists outside of self-regulation at the moment. Sometimes it takes this kind of political interest to move forward those who have been resistant to taking seriously issues around accountability, transparency and openness.'
However, as PRWeek went to press, there was no indication that two of the biggest consultancies outside of the APPC, Bell Pottinger Public Affairs and Luther Pendragon, were planning to change their stance.
Meanwhile, campaigners for greater transparency in lobbying said the Tories needed to be tougher with the lobbying industry. In particular, campaigners noted that the Tories had failed to set a deadline for all lobbyists to reveal their client lists voluntarily.
Spinwatch spokesman David Miller said: 'We are a bit sceptical about the plans. We think this is the Tories being soft on lobbyists.'
In addition, the Tories have said the solicitors' code of conduct should be amended so solicitors' firms that engage in public affairs work can disclose their lobbying clients without breaching that code. DLA Piper director Eben Black welcomed this, saying: 'We have been calling consistently for a statutory register.'