Balfour Beatty, Carillion, Costain, Kier, Laing O’Rourke, Sir Robert McAlpine, Skanska UK and VINCI have settled the litigation between them and individuals represented by UCATT, GMB and legal firm GCR.
The companies have made a full public apology which has now been accepted by the unions and GCR.
Campaigners estimated that settlements so far have hit £50m.
Blacklisted workers represented by the Unite union are yet to settle with a High Court hearing due to start next month.
A statement from the contractors said: “These construction companies now wish to draw a line under this matter and continue to work together with the trade unions at national, regional and site level to ensure that the modern UK construction industry provides the highest standards of employment and HR practice for its workforce.”
UCATT said: “The construction companies have offered financial settlements which all claimants represented by UCATT, GMB and GCR have now accepted as fair and reasonable.
“The parties have also agreed a joint statement to be read in Court as part of this settlement. The construction companies have also agreed to pay the claimants’ legal costs.
“Given that there remains outstanding litigation between the construction companies and other litigants with a trial due to start on 9 May 2016, it would be inappropriate to make any further comments at this stage.”
Steve Acheson, chair of the Blacklist Support Group said: “The construction firms may ‘wish to draw a line under this matter’ but for blacklisted workers this is still unfinished business.
“Until such time that the the full conspiracy is exposed and those responsible for the human rights abuse are called to account in a court of law, we will never stop fighting”.
Unite director of legal services, Howard Beckett said: “Unite is continuing to litigate on behalf of those construction workers whose lives were ruined by the ‘blacklisting’ scandal.”