There are now a total of 65 patients being treated for Covid at Letterkenny University Hospital.
The number of such cases has increased dramatically from 42 a week ago.
The hospital is now under severe pressure because of the rise in the number of patients being kept in because of their condition due to Covid.
The hospital was forced to cancel all elective surgery last week as the number of Covid patients grew.
People are being advised not to attend the hospital directly but to consult with the NowDoc service instead.
Staffing at the hospital is also under severe strain with up to 170 members of staff off due to Covid.