Two wards at Ninewells Hospital have stopped accepting new admissions after asymptomatic patients tested positive for coronavirus.
NHS Tayside has confirmed ward eight and ward 12 are now no longer accepting new admissions as a result.
Staff at the hospital do routine asymptomatic testing on patients entering hospital in a bid to stop the spread of Covid-19.
However this does mean at times patients who are in non-coronavirus wards and are asymptomatic can test positive.
A spokeswoman for the health board said: “No wards at the hospital are closed, but wards eight and 12 are not currently accepting new admissions.
“We do routine asymptomatic testing in various wards and in patients over the age of 70, and occasionally there are people who are asymptomatic and we get positive cases.
“[There are] positive cases in both wards and are not accepting new admissions.”
Second major outbreak at 2 Sisters
Meanwhile, the number of positive Covid-19 cases at the 2 Sisters chicken factory have soared to 30.
NHS Tayside confirmed the increased number of confirmed coronavirus cases which has risen from seven last week.
An incident management team has now been set up to deal with second major outbreak at the Perthshire plant.
Dr Emma Fletcher, director of public health at NHS Tayside, said: “Thirty cases of Covid-19 connected to the 2 Sisters food processing plant have now been identified.
“The factory is working closely with NHS Tayside’s Public Health team and Food Standards Scotland and all arrangements for contact tracing and self-isolation are in place.
“Staff are being given appropriate advice and additional support from their relevant Local Authority if needed.
“The multi-agency Incident Management Team (IMT) continues to keep the situation under close review and the factory remains open.”
All 900 staff and their households were sent into quarantine during the earlier outbreak in August.
A mobile testing station was set up by the military in the grounds of the factory, while other units were put in place for staff in neighbouring Dundee and Angus.
Huge efforts were made by Perth and Kinross Council to encourage all staff to get checked, with information packs produced in Bulgarian, Polish and Romanian.
Food parcels were delivered to workers isolating at home throughout the two-week quarantine.