The company, known as Active Labour, has provided building workers to the Barangaroo South construction site, including workers employed through the site's Aboriginal employment program.

Building industry sources said that senior figures within the Construction, Forestry, Mining and Energy Union organised for Mr Alex's firm to gain access to work at Barangaroo, including involvement in the indigenous labour program.

The union figures use their influence to ensure the companies linked to crime figures and outlaw motorcycle gangs get the CFMEU's backing, including enterprise bargaining agreements, to win contracts on big private and government projects

Mr Alex's business affairs are deeply entwined with known bikie and organised crime networks. Joe Antoun, a standover man who worked in the building industry, was Mr Alex's right-hand man until he was shot dead in front of his family in Strathfield last year.

Former Comanchero and convicted criminal Bilal Fatrouni appears to have replaced Antoun, well-placed sources say. Those sources have also confirmed Mr Alex's business ventures include involvement by drug traffickers and bikies and it is understood drug money has been invested into his businesses.

Gaining access to Barangaroo and its indigenous employment program provides Mr Alex with a potentially lucrative income stream.

A spokesman for the principal contractor at Barangaroo South, Lend Lease, told Fairfax Media that the construction firm has no direct involvement with Active Labour. ''As is standard practice in the construction industry, our subcontractors may, in turn, have commercial arrangements with other entities with whom we do not have direct dealings,'' the spokesman said.

Lend Lease said there are more than 40 people of indigenous heritage working at Barangaroo, mainly in construction roles. It said it does not pay financial incentives to companies employing Aborigines.

One of the Aboriginal workers employed at Barangaroo died on the site on January 9. The 23-year-old man from the south coast was employed by Active Labour.

His death has highlighted Mr Alex's foothold at Barangaroo and raised questions over mentoring programs associated with the employment scheme through Active Labour. The deceased man had been on the job for only two weeks after attending an eight-week training course at Koori Job Ready, which is run through the National Centre for Indigenous Excellence.

''The only mentoring that happens is at the start of the job, before they start on site. Where was the supervision that should have been carried out when this worker arrived on the site this morning [January 9]?'' CFMEU state secretary Brian Parker said at the time.

Mr Alex was at Barangaroo South on January 10 while the site was closed during investigations into the death. A police statement said the death was not related to workplace or safety concerns.

Mr Parker confirmed the CFMEU has an enterprise agreement with Active Labour. The union also confirmed there are only about a dozen labour-hire firms with union agreements in NSW.

When asked by Fairfax about the relationship between Active Labour and the CFMEU, Mr Parker said: ''The CFMEU has no agreement with Active Labour Hire with regard to the Koori Job Ready Program for the Barangaroo project.

''The only agreement the CFMEU has with Active Labour Hire is an EBA …,'' he said.

Fairfax contacted Koori Job Ready and the National Centre for Indigenous Excellence but they were unable to respond by the time of publication.