Competition regulator Graeme Samuel has moved to clear the air over a bitter controversy surrounding attempts to lay criminal charges against the late billionaire and Visy boss, Richard Pratt.

Speaking on video on Wednesday with Alan Kohler, Robert Gottliebsen and Stephen Bartholomeusz, Mr Samuel highlighted the crucial role played by the Director of Public Prosecutions (DPP) in the legal process which led to criminal charges being laid against the packaging king.