A construction union official and former NRL star charged with blackmail during the trade unions royal commission has received a payout courtesy of the Australian Federal Police.

John Lomax, an official with the ACT branch of the CFMEU, was originally charged with blackmail in July of 2015, but the charges were dropped just months later.

The allegations stemmed from evidence aired during the royal commission, which Mr Lomax and his colleagues have maintained was politically motivated.

Mr Lomax, who is also a former Canberra Raiders player, took the AFP to court over the bungled prosecution, and on Friday police confirmed the case had been settled.

The amount paid to Mr Lomax remains confidential, but CFMEU national secretary for construction Dave Noonan called for it to be made public.

"This settlement should not be kept secret from the taxpayers who are forced to fund it," he said.

Mr Lomax was one of three men charged during the royal commission's Canberra hearings. It had been alleged he made a demand with menace while negotiating a pay deal with a construction company.

But Mr Noonan said he had been prosecuted for representing his members' interests.

"The allegation was that he got his members a pay rise through negotiating an enterprise agreement and that was never going to be a charge that could be proven in court," he said.

"Negotiating better wages for members is what unions do — it's not blackmail.

"There's no doubt this was a malicious prosecution, the AFP ensured maximum publicity of the charge."

Another CFMEU official, Fihi Kivalu, pleaded guilty to blackmail charges stemming from the commission, over allegations he pocketed nearly $70,000 in bribes.

A third man, Tuungafasi Manase pleaded guilty to perjury after lying to the commission.

In Victoria on Thursday, prosecutors dropped royal commission-linked charges against CFMEU bosses John Setka and Shaun Reardon.