Nissan, which is one of the biggest employers in the region, has confirmed a deep clean of the area where the employee works was carried out.
The member of staff is now recovering at home and the firm, which employs around 6,000 people, said strict safety and social distancing measures are in place.
Production resumed at the plant last month after Nissan closed factory doors in March in response to the coronavirus pandemic.
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A Nissan spokeswoman said: “We are in daily contact with a member of our team who is now recovering at home.
“We have a thorough and comprehensive set of proactive safety measures in place to protect our staff, including strict social distancing rules, protective screens and PPE provision as appropriate. In line with these controls, a full deep clean of the area where this person works, including all tools and equipment, was carried out as soon as he displayed symptoms.
“We will continue to follow all public heath guidelines and work closely with our staff and their representatives.”
The firm had carried out hundreds of hours of preparation to ensure the safe return of employees before the plant reopened on June 8.
Nissan said every operation across the plant had been rigorously risk assessed to make sure it is safe, with more than 5,000 processes reviewed to ensure safety at all times.
The confirmed case comes just weeks after Sunderland City Council bosses said they would consider temporarily shutting down Nissan or other major employers if they were linked back to a coronavirus outbreak.
As the government continues to roll back its Covid-19 lockdown measures fears have focussed on the potential for a ‘second spike’ in infections as families return to school and workplaces.
Councils currently only have limited powers to try and enforce ‘local lockdowns’ but leaders have insisted they will use them if they prove the best way of keeping the virus at bay.