A fire safety review is under way at Peterborough City Hospital after checks revealed issues with the ceiling voids.
Bosses at the £289 million hospital, which opened in November 2010, are concerned the voids might not comply with standards designed to stop the spread of smoke and flames.
The issue was raised after checks were carried out in response to a national directive from the Department of Health in October.
Bosses say it is not clear if the problem dates back to the construction of the hospital or is due to a change in standards.
However, a spokesman for the construction firm said the building was thoroughly tested before the hospital opened, has been maintained and has been subjected to annual fire risk assessments.
A more detailed investigation across the whole hospital is now being carried out by the Peterborough and Stamford Hospitals NHS Foundation Trust to discover how serious the situation is.
At the same time bosses are reviewing the fire evacuation procedure and staff have been asked to be aware of fire danagers.
Stephen Graves, the trust’s chief executive, said: “Following a review of the fire safety standards to which our hospital has been built, we have learned of some potential issues with the infrastructure.
“The scale of these issues is not yet clear, however we have immediately discussed them with Progress Health, the organisation which has responsibility for maintaining the City Hospital building, who are treating the matter with the utmost urgency and have commenced an independent study of the building.
“ We, together with Progress Health, are working to investigate and resolve any potential issues.
“As a precaution we have notified the fire service and have taken the decision to review our fire evacuation procedure.
“We can assure our patients, staff and visitors that we will remain vigilant in ensuring fire safety standards are maintained at all times.”
A fire service spokesman said they were working closely with the trust to ensure the safety of patients, staff and visitors.
A Peterborough City Council spokeswoman said: “We were involved in signing off the building regulations on the new hospital on September 7, 2010. These included checks on fire separation. We were happy the building was compliant in all areas.”
A spokesperson from construction firm Brookfield Multiplex said: “We are extremely concerned by a number of unsubstantiated allegations made in the report into fire safety standards at Peterborough City Hospital.
“The product was thoroughly tested prior to hospital operation and has been maintained throughout and been subjected to annual fire risk assessments by the trust.
“All life safety systems continue to be 100 per cent operational and tested.
“Since being made aware of potential issues relating to recently found small breeches in fire compartments we have had resource on stand-by to investigate and attend to issues immediately, if required.
“The nature of the issues raised in the report are minor and can be rectified in hours if relevant locations are identified, which has yet to happen despite repeated attempts to obtain this detailed information from the trust.
“We have since been instructed to stop our investigation and remedial works by Progress Health.”