Top Energy chief executive Russell Shaw said one staff member at the Kerikeri office had tested positive, but had fully recovered and had gone back to working from home on Monday. Hospital treatment had not been needed.
Mr Shaw said the office had been sanitised and nine work contacts had gone into isolation. All had tested negative, which he put down to good social distancing within the workplace. All office staff were now working from home.
Field staff were continuing to work - "we still have to keep the power on" - but were disinfecting tools between jobs, maintaining social distancing and staying within their own work bubbles.
"The guys have been very careful and are doing an excellent job. They don't want to take this stuff home," Mr Shaw added.
No new Northland cases were reported on Tuesday, keeping the number of confirmed and probable cases in the region at 27. One patient remains in a stable condition at Whangārei Hospital, while 12 people are self-isolating at home and 14 have recovered.
Mr Carter told councillors to expect strict rules about how people interacted even after the Level 4 alert was lifted.
"Handshakes and hongi will not be part of our community for some serious time," he said.