Chorus and its subcontractors should have done more to identify and mitigate the risk of breaches in employment law, an independent report has found.

In October last year the board of Chorus commissioned company Martin Jenkins to investigate its subcontractors' employment processes.

The move followed a Labour Inspectorate report that found 73 of 75 Chorus subcontractors systematically exploited workers.

The report, released today, found the adoption of a subcontracting model for the delivery of the ultra-fast broadband network was appropriate and that use of migrant workers by Visionstream and UCG was both expected and reasonable given the significant demand for labour and time-limited and one-off nature of the work required.

But it found that as the proportion of migrant workers increased the subcontracting model became increasingly vulnerable to the risk of labour exploitation.

"This risk was not well understood nor adequately managed by Chorus, Visionstream or UCG."

The report found the approach taken to the risk was not "sufficiently adequate" given the complex nature of migrant exploitation.

"The subcontracted model has been applied by Visionstream and UCG in such a way that the risks associated with volatility of demand for UFB connection may be disproportionately borne by the end technician."

It said Chorus and the service companies contracted to it would benefit from a more joined-up approach to workforce strategy and a "shared understanding of needs, pressures and risks, with a particular focus on potential impacts on the viability of individual crews."

Chrosu CEO Kate McKenzie says there was not enough oversight into how subcontractors were treating workers.

"What tends to happen in these environments is you  focus on the thing in front of you right now, With the benefit of hindsight, it would have been nice that more attention was paid to it, but we've got it now."

McKenzie says they have not apologised to the workers. They have, however, had a number of conversations with them them to make sure the companies are doing right by them.

Joe Gallagher from the E Tu Union told Mike Yardley that the report has highlighted that there is a serious problem of exploitation.

He says it is disappointing that McKenzie says that hindsight is a benefit. 

"When they brought in Vision Stream, they made a decision to bring in a model that created arms-link responsibility, and here we are eight links down the track and we have large scale exploitation. The fact they couldn't even apologise today is quite disappointing."

Gallagher says that some of these workers were working voluntarily and not taking sick or holiday leave in order to get jobs with other contractors.

"The issues are really an example of when you don't have proper oversight over an industry, you just open Pandora's Box to exploitation." 

As the rollout is still going on throughout the country, Gallagher says that the exploitation is ongoing. 

He would like to see the creation of an employment environment that would prevent this type of exploitation taking place.