Some weddings might have to be moved, after mould was found in rooms used for ceremonies and council meetings at Newcastle's Castle House civic centre.
Penicillium spores have been found in the Astley Room and the Garden Room on the ground floor of the £15.4m building, following a water leak earlier this month.
A handful of rooms were temporarily closed at the time, but have again been shut following the discovery of the mould.
The County Council, who use the building along with Newcastle Borough Council, Staffordshire Police and Aspire Housing, say that the mould is not hazardous, but when concentrated in the air like this can affect those with conditions such as asthma.
Mark Deaville, Staffordshire County Council’s Cabinet Member for Commercial, said: “After taking expert advice we have decided to temporarily stop using the function rooms until a thorough clean-up operation can take place.
“Whilst this is very disappointing, the safety and wellbeing of the people who visit or work at Castle House must be our primary concern no matter how small the risk.
“We are really sorry that we have had to close the function rooms at such short notice and apologise for any inconvenience it causes.
“We will be holding wedding ceremonies in alternative rooms or locations depending on the size of the party so couples can still enjoy their celebrations with family and friends.”
A decision will be taken early next week as to where public meetings will be held.
Cllr Deaville added: “Castle House was designed to bring public services under one roof making accessing them easier for taxpayers – and saving millions of pounds in running costs and boosting the local daytime economy in the town.
“So while the closure of the function rooms is disappointing. It will be very much business as usual for all other public services and facilities and we look forward to seeing the rooms back in use as quickly as possible.”