Prime Minister Tony Abbott's chief of staff has come under fire yet again for her controversial decision to ban Labor appointments from retaining their positions on government boards. The move by Peta Credlin has been derided by the business community  as 'unrealistic' because nearly all of the directors on government boards were employed during Labor's six-years in government. Speaking at an Australian Institute of Company Directors lunch, chairman of CSIRO, Simon McKeon confirmed the ban on Labor appointees to government boards, claiming he will lose his position when his contract expires in June. Scroll down for video . Prime Minister Tony Abbott's chief of staff, Peta Credlin (pictured) has come under fire yet again for her controversial decision to ban Labor appointments from retaining their positions on government boards. 'Labor was in power for six years. Virtually everybody currently serving on the boards of government bodies was either appointed or reappointed while Labor was in power,' Mr McKeon said. 'If Abbott persists with his policy, there will be a full clean out of directorships.' 'The reality is that, yes, there is a rule that no one on the board of a federal government agency has been reappointed,' Mr McKeon said. 'It's an issue that many people are finding worrying.' Mr McKeon, who is also chairman of AMP, said the policy was at odds with what the AICD and Business Council of Australia subscribed to as good governance. 'My understanding is that there are many people like me who are disappointed with this quite brutal rule,' he said. 'I haven't come across anyone actually in government, let alone in private enterprise, who says `oh this is a wonderfully good initiative'.' Takeovers Panel member and Telstra director Dr Nora Scheinkestel said the panel's size had been significantly reduced as members had not been reappointed when their terms came up. In February, it was revealed that Peta Creddlin was at loggerheads with top Cabinet Ministers over her attempts to micro manage Julie Bishop and steal Joe Hockey's thunder . 'The reality is we lost a lot of people who brought great expertise, major institutional investors, investment bankers etc, and I think it's to the detriment of how the panel functions.' Mr McKeon said Australia needed excellent people on these challenging boards. 'The last thing we want to be doing is to one kick them off after three years, let alone send a very strong message saying this is the way it ought to be.' Dr Nora Scheinkestel, a director of Telstra, said she was strongly against the rule, as was chairman of BlueScope Steel Graham Kraehe. McKeon is a former Australian of the Year and is coming up for reappointment in following months, like many of his colleagues. Many of them are part of the boards for humanitarian or charitable reasons. 'My understanding is that there are many people like me who are disappointed with this quite brutal rule,' he said. But Abbott's devotion to Credlin is unmoving. The prime minister has defended her time and time again, calling her 'the fiercest political warrior I've ever worked with' In February, it was revealed that Peta Creddlin was at loggerheads with top Cabinet Ministers over her attempts to micro manage Julie Bishop and steal Joe Hockey's thunder. Foreign Minister Julie Bishop is understood to have been involved in a feud with Credlin after her extensive attempt to micro manage the government included controlling minister's media appearances. Meanwhile, Treasurer Joe Hockey's grievances with Credlin are also understood to have stemmed from her tendency to over-step her mark and take control. At a small celebration following the release of the party's first budget, Credlin undermined the Treasurer by having the first word - leading the toast, and ultimately taking ownership of an accomplishment that should have been Hockey's to savour. But Abbott's devotion to Credlin is unmoving. The prime minister has defended her time and time again, calling her 'the fiercest political warrior I've ever worked with'. He is known to have told associates that raised complaints against her: 'you wouldn't be here if it wasn't for Peta'. Meanwhile, Tony Abbott's future remains uncertain with some disgruntled MPs claiming it is only a matter of time before the leadership issue comes to a head.
Peta Credlin has banned Labor appointees from keeping their jobs . It was confirmed at an Australian Institute of Company Directors lunch . It has been met with outrage from the Coalition and business community . Many of the appointees do the job for humanitarian reasons . Tony Abbott is a staunch supporter of Credlin calling her a 'political warrior'