Five upper floors at the northeast corner of Calgary's Municipal Building have been closed after work crews discovered a structural deficiency.

City officials don't believe there is an immediate risk to the safety of employees or the public but said in a release Monday morning that they decided to close that section of the building "out of an abundance of caution."

Floors eight through 12 of the Municipal Building and the Administration Annex Building are closed.

The deficiency was discovered in a structural component of the building, which does not appear to meet building safety codes.

"The city holds itself to the same high standards it holds other building owners in regards to safety," facilities management director Thomas Hansen said in a release.

"Safety is always top priority and while we investigate we want to ensure employees and members of the public visiting the Municipal Building that we are working to ensure it is safe."

Hansen later updated city council on the situation, saying the problem relates to a 30,000-kilogram truss that was incorrectly installed more than three decades ago.

Diagrams presented to city council on Monday showing the location of a truss that was incorrectly installed in the Municipal Building three decades ago. The problem was only discovered on Friday Sept. 16, 2016. (Screenshot)

"This truss has been in place since the building was constructed in 1983," Hansen said.

"There are no signs of any imminent collapse or structural issues."

Employees whose offices are in the closed area will be relocated while that section of the building is examined. The city warned that may take "considerable time" to complete as work is expected to continue "throughout the coming weeks."

Historic old city hall, located just north of the Municipal Building, is currently undergoing a multi-year, $34-million planned renovation that has displaced the offices of the city councillors.