Local authorities and public bodies are being urged to stop giving work to companies involved in the blacklisting of construction workers.
The scandal has cost leading building firms tens of millions of pounds after an out of court settlement was reached last month.
About £50 million was paid out in compensation to 771 workers, with union legal costs estimated at £25 million.
Some of the workers involved in the outrage won applause at the annual conference of the GMB union in Bournemouth.
They talked about the impact on their lives of being on a blacklist, which denied them work.
Mike Raynor, 52, from the Wirral, found he was even blocked from working abroad because his name was included on the list. "I couldn't even get work in countries like Hong Kong," said the scaffolder, who was sacked from working on a building site in Connah's Quay in north Wales, two weeks after being elected a union shop steward.
Peter Feather from Rotherham found out in 2010 that his name was on the blacklist, again because he was a shop steward. "I only got agency work after that. What happened was disgusting. It affected my family as well as me." The 58-year-old labourer said the agreement to offer retraining to workers affected by the scandal was of no use to him now.
Justin Bowden, national officer of the GMB, said "Having established that the construction companies lied and denied before finally caving in and paying their way out of a hugely embarrassing trial, it is time now for local authorities and other public bodies to stand by their promises to stop using blacklisting companies.
"GMB will be ensuring all local authorities are fully informed about their obligations in relation to procurement and blacklisting companies, and where taxpayers' money is spent."
Maria Ludkin, the GMB's legal director, said: "The companies have never formally acknowledged that they were blacklisters, despite settling all claims and apologising for their actions, which looks like blacklisting, smells like blacklisting and tastes like blacklisting.
"In GMB's view that does not show appropriate remorse, nor meet the test of self-cleansing and a desire to reform. In those circumstances our campaign goes on."
Blacklisting came to light in 2009 when the Information Commissioner's Office seized a Consulting Association database of 3,213 construction workers and environmental activists, used by 44 companies to vet new recruits and keep out of employment trade union and health and safety activists.
Balfour Beatty, Carillion, Costain, Kier, Laing O'Rourke, Sir Robert McAlpine, Skanska UK and Vinci said last month they had settled the litigation, bringing an end to all legal claims.
"These construction companies 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 (human resources) practice for its workforce," a statement said.
Labour leader Jeremy Corbyn repeated his support for a public inquiry into blacklisting when he addressed the conference.
He agreed that public procurement should be used to ensure contracts are only given to companies that recognise workers' rights and do not blacklist anyone for union activities.
"I don't see why that should not be part of our central policy," he said to loud cheers from delegates.