Tasmanian Senator Jacqui Lambie says she was "absolutely flabbergasted" at the secret volumes produced by the trade union royal commission.

But not in the way you might think. She was flabbergasted because the documents contained nothing of the grave threat to the power and authority of the Australian state she was promised by Royal Commissioner Dyson Heydon.

"I was thinking, oh my God, what are [sic] in these secret volumes," Senator Lambie told the ABC's Q & A program on Monday night.

Jacqui Lambie will not vote in favour of legislation to re--establish the construction industry watchdog, which could help trigger a double dissolution election on July 2. Alex Ellinghausen

"I can tell you...I came out of there and I was absolutely flabbergasted. I don't know what the Royal Commissioner is trying to pull here, but there is nothing that even resembles anything that is a grave threat to the power and authority of the Australian state."

The government is using the findings of the royal commission to bolster its case for re-establishing the Australian Building and Construction Commission (ABCC).