A farmer/fisherman is challenging the decision to grant a licence for the Irish leg of the project for a transatlantic sub-sea cable system, connecting northern Europe and the US.
James O'Toole is opposing the landfall for the Irish branch of the system called America Europe Connect 2, owned by a consortium of IT companies, including Facebook and Google.
It is a notice party to proceedings against the Minister of State at the Department of Planning and Local Government, which granted a foreshore licence earlier this year.
The transatlantic fibre optic cable extending from the US to Denmark, with spurs to Ireland and Norway, is under construction.
The planned route for the Irish spur includes a landfall at Old Head on the southern side of Clew Bay, roughly three kilometres from Louisburgh, Co Mayo.
Mr Justice David Barniville yesterday admitted the case to the High Court's fast-track Commercial Court division.
Mr O'Toole is challenging the granting of a foreshore licence to bring the cable ashore at Old Head.
America Europe Connect 2, which applied to have the case entered to the commercial list, contends it is a major infrastructural project of significant importance here.
David Holland SC, for the consortium, told the court a technical team was already at a Mayo hotel in self-isolation and expecting to start work next week.
James Devlin SC, for Mr O'Toole, said his client will also be applying to the High Court for a stay on any work being carried out pending a court determination on the legal challenge.
Mr O'Toole, of Ballytoughey, Clare Island, described in the court papers as a farmer and fisherman, is seeking an order quashing the decision of the minister on February 6 to grant a licence under the Foreshore Act to install the cable on the Old Head foreshore.
He is also seeking a declaration that the decision to grant the licence was outside the minister's powers and contrary to the EU Habitats Directive. He has claimed the decision lacked sufficient reasons and was contrary to fair procedures.
He has claimed the shortest possible route to Ireland's shore was selected even though it is through areas of rocky seabed, where the cable cannot be buried, and sensitive fishing grounds in Clew Bay.
It passes through the narrow channel between Achill and Clare islands. The hearing on whether a stay should be granted until the legal challenge is determined will be decided later this week.