Fair Work Building and Construction cited nine appeal grounds in its challenge to Justice Geoffrey Flick's original decision.

However, the court on Thursday ordered the appeal be dismissed.

In the original case against the union's former ACT branch secretary Dean Hall and his colleagues, ABCC alleged the union had blockaded the Dickson site over three consecutive days in June 2014 on the false pretext of being concerned about safety.

The commission claimed the blockade had been actually put in place to force the builder to sign a CFMEU enterprise agreement.

The ABCC claimed the union's actions amounted to 36 breaches of the Fair Work Act.

The court heard from witnesses who alleged some of the union officials offered to end the safety dispute if the company signed the agreement and that Mr Hall threatened a "war" after police were called to the blockade.

One witness was disgraced former union official, Halafihi Kimonu Kivalu, who had been convicted of blackmail, who had cut a deal with the watchdog to testify against his former colleagues in order to dodge a jail sentence.

In dismissing the original case, Justice Flick found that the ABCC had not met the burden proof to substantiate his allegations and placed "no reliance" could be placed on Kivalu’s evidence.

CFMEU ACT secretary Jason O’Mara said the decision to dismiss the appeal on Thursday had been "another win for workers and another disaster for top hat Turnbull and gang".

"While workers continue to be killed and maimed, the Liberal Government and ABCC continues to after the unions protecting workers."