Trade union royal commission to grill Canberra CFMEU

The Canberra branch of the construction union will be in the spotlight as hearings resume at the trade union royal commission.

Fresh from grilling Opposition Leader and former Australian Workers Union national secretary Bill Shorten, the commission has made its way to the nation's capital for three weeks of hearings starting on Monday.

Nearly 40 witnesses are listed as it inquires into the ACT CFMEU, including its branch secretary Dean Hall.

The probe comes as the union faces Federal Court action for allegedly organising a three-day blockade at a Canberra building site, after the head contractor raised concerns about a proposed enterprise-bargaining agreement.

The CFMEU has also called for investigations, recently writing to the Fair Work Ombudsman asking it to look into sham contracting.

Master Builders has welcomed the hearings, saying workers are finding the courage to speak up against the union's tactics.

Like other unions and federal Labor, the CFMEU has described the commission as a witch hunt.