Speaking to affiliated union members in Brighton, he said the government needed to address labour market inequalities to make Britain fairer.
"What can the government do to turn fairness from a political slogan into a practical reality?" Barber asked.
"First - remove once and for all the worst injustices from our labour market.
"Follow up the agreement on agency workers by ending bogus self-employment and delivering equal rights for homeworkers.
"Make enforcement of the current law much more effective, especially in those sectors and businesses where the risks are greatest.
"And introduce a new Fair Employment Commission to lead the fight against vulnerable working and raise awareness where it matters most."
Barber also called for a more progressive tax system, and for more public provision of education, transport and justice services.
The TUC Congress ends on Thursday.