Labor wants Heydon to show all Lib letters

Federal Labor is demanding the release of all correspondence between royal commissioner Dyson Heydon and the organisers of a Liberal Party event he agreed to address.

Mr Heydon withdrew from the Sir Garfield Barwick Address, telling organisers if there was any possibility it could be described as a Liberal Party event he couldn't do it while presiding over the royal commission into trade union corruption.

Opposition Leader Bill Shorten told ABC radio on Friday the event was clearly organised months ago and all the correspondence, including the initial invitation to Mr Heydon, needed to be released to give the public a full picture of what had been known.