The three-week strike that has stopped construction activities at different Grollo sites has just ended. The Construction, Forestry, Mining and Energy Union (CFMEU) lifted its blockade at the Myer Emporium job site, prompting Grocon Chief Executive Daniel Grollo to agree to resume negotiations with the union.

Prior to the CFMEU decision Thursday night to unconditionally end the blockade, the industrial action has spread to four Grocon construction sites and cost the firm thousands of dollars in losses.

Mr Grollo, who announced the end of the industrial dispute, said that with the CFMEU decision, all Grocon workers could return to their job sites safely. During the blockade, the police had to secretly escort non-union employees who wanted to continue with their jobs to the construction sites.

Even before the CFMEU decision, the union ended its blockade on Wednesday at the Victorian Comprehensive Cancer Centre due to a backlash from cancer patients. The other Grocon sites affected by the protest action were at the Myer Emporium, Westpac building in Collins Street and the Footscray office building.

The heart of the industrial dispute was safety issues over the appointment of safety representatives whom Mr Grollo said could not be made by Grocon or the CFMEU but be elected by employees based on rules of the Victorian Occupational Health and Safety Act 2004.

"Grocon employees - who include CFMEU members - have already elected their safety representatives and have told us they are happy with their choice," The Herald Sun quoted Mr Grollo.

Fair Work Australia brokered the end of the industrial row.

"We never like having serious disputes . . . But look, there are some very important principles at stake here - the principle of workers not to be told by their employer who's going to represent them in union matters, not to be dictated to about who'll represent them about safety matters in what is a very high-risk industry," CFMEU Construction Division National Secretary Dave Noonan was quoted by The Herald Sun.

CFMEU State President Ralph Edwards warned Grocon that it the firm does not hold the discussions in a proper way and it would not produce positive results, the blockade would be back.

The protesting workers left the Emporium site at about 6:30 a.m. on Friday.