They included civil, building, and electrical works, building an uninterrupted power supply and heating and ventilation systems. Up to 20 people would be involved in the project, he said.
McKay will shortly apply to the Kaipara District Council for resource consents.
"The project is a pat on the back for us and other Northland-based companies helping with the design and build.
"It's a good vote of confidence in Northland's ability to undertake complicated projects," Mr Faithfull said.
Chief executive of Hawaiki Submarine Cable LP Remi Galasso said the contract won by McKay represented a key step forward for the cable system's movement to New Zealand.
"We are proud to participate in the economic development of Northland and are confident that McKay will deliver this critical piece of infrastructure in the most efficient and timely manner," he said.
The project has also gained a $15 million capital contribution from Government-owned research network company Research and Educational Advanced Network New Zealand.
The Government has provided the $15 million contribution from an appropriation set aside for purchasing an anchor tenancy on a new transtasman and trans-Pacific submarine cable.
Permitting and initial route planning for the cable began in June 2015.