Berwick MP Anne-Marie Trevelyan, Secretary of State for International Development, took the decision after being in close contact with an MP who contracted coronavirus.
She was at the same Downing Street function to mark International Women’s Day as health minister Nadine Dorries.
A spokeswoman for Ms Trevelyan said: “Anne-Marie had close contact with Nadine Dorries at the International Women's Day reception. As a result, she was tested for coronavirus.
“The test came back negative, but she has been advised by doctors to self-isolate for a further seven days in case symptoms develop.”
She cancelled a full day of scheduled engagements in the constituency on Friday but conducted her surgery by telephone and is continuing to work remotely.
“She has not developed any symptoms and is following medical advice,” added the spokeswoman.
Key advice for all residents remains the same.
The recommended steps everyone should take to protect themselves are maintaining good hand, respiratory and personal hygiene: wash your hands often with warm water and soap; use tissues to trap germs when you cough or sneeze; bin used tissues as quickly as possible.
Liz Morgan, Northumberland County Council’s Director of Public Health, said: “Maintaining the safety of all our residents remains our top priority, and we continue to work with our partners to closely monitor developments nationally and internationally.
“All the information available continues to suggest that in the vast majority of cases, this is a mild illness.”