Explosive allegations and evidence have been aired at the trade union royal commission.

It appears that up to 7 tonnes of documents were destroyed within days of the Construction, Forestry, Mining and Energy Union (CFMEU) being subpoenaed by the commission.

Former CFMEU president Dave Hanna told the inquiry that truckloads of records were removed from CFMEU offices and delivered to his property at the request of then CFMEU divisional state secretary Michael Ravbar.

It was right around the time the royal commission requested access to the documents.

The commission was played a seemingly damning audio recording of a conversation between Mr Hanna and the union's national assistant secretary, Leo Skourdoumbis.

In the recording, Mr Hanna told Mr Skourdoumbis he had organised a tip truck “that dumped seven tonnes of documentation the day we got the subpoenas to provide all the paper work on the 1st of April, April Fools' Day”.

The recording has been transcribed here;

Mr Hanna: ... Ravbar had all the training coordinators come in, his daughter to come in and do shredding yadda yadda. Loaded up two horse float trailers.

Mr Skourdoumbis: Can't blame him for that.

Mr Hanna: Hey?

Mr Skourdoumbis: Can't blame him for that.

Mr Hanna: No you can't. But um got all that done, there was f***ing mountains and mountains of ...(indistinct) ... seven tonnes' worth.

Mr Skourdoumbis: Really?

Mr Hanna: Yep, it was weighed, the truck was weighed when it got dumped that's how much f***ing paper, paper is heavy. Paper is heavy. It all got taken down to my f****ing joint where he stores his f****ing car trailer and he stores his caravan. 

Mr Skourdoumbis says he did not follow up the allegations or report them to officials.

Mr Hanna told the commission he embellished the details in the audio recording, and that he did not have any concerns that the documents would be needed by the royal commission.

It comes just a week after Mr Hanna claimed he thought that $100,000 worth of renovations to his house that were allegedly billed to the backers of a shopping centre project were done for free because he is a “good bloke”.