The company running the Corrib Gas field has confirmed that three UK-based contractors, who travelled to Ireland to carry out maintenance work at the Bellanaboy terminal in Co Mayo, have tested positive for Covid-19.
Vermilion Exploration & Production said the workers were among a group of 70 people engaged to carry out maintenance works at the terminal in recent weeks. All travelled here from abroad.
The company said that it "pro-actively" tests all non-Irish contractors when they arrive in the country.
It says that the three individuals in question were tested on the day they arrived in Ireland and have restricted their movements. They will quarantine for the next 14 days and will be tested again before being allowed to work.
The other 67 foreign-based contractors, who arrived here in the last fortnight, are also being re-tested.
Vermillion said it has followed the protocols and advice issued by the HSE, the Department of Health and the Department of Foreign Affairs.
It is understood local staff at the terminal were informed about the positive test results involving the contractors by email.
Vermilion said that all personnel travelling from abroad are tested for coronavirus on their arrival and restrict their movements until a negative result is confirmed. If that happens, they are then free to travel to and from their accommodation to work.
When they are not at work they are required to restrict their movements, in line with public health advice.
Vermilion said the contractors in question have specialist expertise that is not available in Ireland and are carrying out critical work.
It said that EU guidelines allow for them to enter the country and have "unhindered access to their place of work".