"The best of my recollection is that I saw the notice to produce probably about later in the morning of the 2nd of April," he told the trade union royal commission on Thursday.

Mr Ravbar's personal assistant and a governance manager at the union's Brisbane headquarters also denied seeing the emailed notice to produce documents, which was sent through at 4.16pm on April 1, 2014.

On Wednesday, the inquiry heard Mr Ravbar and his staff worked into the night of April 1 shredding files and preparing others for destruction.

But Mr Ravbar said that date had always been intended as the deadline to complete a recent merger with the Builders Labourers Federation.

He said a "phenomenal" amount of BLF material had arrived in boxes at the CFMEU's Brisbane offices and he spent March 28, 31, and April 1 sorting through it.