Halafihi Kimonu Kivalu, 39, allegedly blackmailed a subcontractor while working with the CFMEU, telling him to give him money to "get some people off your back".

Kivalu - a union organiser between 2010 and November 2014 - was arrested after damning covert recordings were played to the royal commission, purporting to show him demanding money from formwork subcontractor Elias Taleb.

He allegedly blackmailed Mr Taleb in relation to a residential development at Yarralumla between March 2012 and May 2013, and an apartment complex development in Braddon between October and November 2013.

"Kivalu made it clear to Taleb that if he did not pay him $50,000 to secure the Yarralumla site, one of his competitors would pay and the work would go to them," police alleged in a statement of facts.

It is alleged that Mr Taleb thought he needed to make the payments to the CFMEU to avoid disruptions on his work sites.

Court documents suggest Kivalu collected tens of thousands of dollars from Mr Taleb.

The former union official, represented by lawyer Toni Tu'ulakitau, had initially pleaded not guilty, planning to fight the two blackmail charges at trial.

But the case appeared again on Thursday in the ACT Supreme Court for directions, where Mr Tu'ulakitau indicated his client would be pleading guilty.

A sentencing date has been set in May, and Kivalu will be arraigned on March 10. He is expected to formally enter the pleas during that arraignment.

Kivalu, also a former president of the ALP's Dickson-Morning sub-branch in Canberra, did not comment as he left the court.

It is alleged that the CFMEU shut down Mr Taleb's Yarralumla site in late 2013.

Kivalu was present and, when questioned about the shut down, allegedly replied:

"Don't worry, we'll sort it out."

He allegedly called Mr Taleb later and said:

"Look I sorted it, but you are going to have to give me some money, let's do the deal."

Mr Taleb is said to have then paid Kivalu $20,000.