Business Secretary Vince Cable told the House of Commons that he could only launch a probe if hard evidence was produced that blacklisting had taken place since it was outlawed in 2010.
He said: “I am very happy to take this forward is there is any issue to investigate.
“It needs investigating if it is still going on – that is the essence of this.
“Are we talking about now or an investigation into history?”
Cable was responding to calls from shadow business secretary Chuka Umanna for a full investigation into construction blacklisting along the lines of the Leveson inquiry into phone hacking.
Umanna said: “I am flabbergasted by the Secretary of State’s response.
“Allegations have been made and need to be investigated.”
Umanna also called for contractors who used the disbanded Consulting Association to make a full apology and set up a compensation fund for affected workers.