Cases of aspergillosis were discovered earlier this year, and the condition is caused by inhaling mold found in dust, damp buildings, air conditioning systems and bedding.
NHS Ayrshire and Arran has confirmed that the cause of the mold is still being investigated and that it has not been decided where patients will be moved to once the ward closes.
Director of Nursing Jennifer Wilson said: “NHS Ayrshire and Arran identified a very small number of patients with aspergillosis on a ward at University Hospital Crosshouse earlier this year.
“We have notified Antimicrobial Resistance and Healthcare Associated Infection Scotland (ARHAI) of the incident in accordance with national reporting requirements and are working closely with them.
“Whilst we have taken remedial measures to complete major infrastructure maintenance on the ward, we are currently investigating alternative ward accommodation to allow these works to be carried out.”
The health board has not released further information about the situation, including the number of patients affected.