Downer EDI has outsourced the design works for a $94 million NBN contract in Northern NSW to Kordia's Australian arm.
Kordia said in a statement it would perform all design works for connecting fibre to homes in that portion of the rollout area.
Downer EDI will use those designs to physically roll fibre to homes under a deal announced back in February.
Kordia said its remit included "network analysis and routing documentation for both underground and aerial components, including coordination with Telstra and electricity utilities."
"A high quality and timely design is critical to the successful and cost effective rollout of the NBN in northern NSW," it said.
Downer EDI and Kordia have previously performed NBN works together in Queensland.