The pipe work is at risk of falling in a seismic event or other situation where force is applied, for example if the sprinkler system were to be discharged.
The fixings supporting the sprinkler pipes to the ceiling must be upgraded to ensure they are of sufficient load-bearing capacity.
"The safety of our staff and customers are our highest priority. We have therefore taken the decision to close this building immediately, to enable the necessary repair work to be carried out safely and quickly," Marshall said.
"We are aware of the inconvenience this closure creates for our regular customers as well as visitors to Napier. We will work to ensure the entire building can open up safely as quickly as we can."
The work in the MTG Hawke's Bay Century Theatre and foyer is expected to be completed in time for the theatre's reopening on Wednesday, January 27.
Work in the rest of the building, including Napier Library, is expected to take longer however.
Council said until further investigative work is completed during January, they are unable to provide an exact time of reopening, but some parts of the building could be closed for several months.
"Where possible, we will look to reopen the building in stages, to help minimise disruption," Marshall said.
Library customers will be able to access services from Taradale Library only, while access to the archives and collections at the MTG off-site store will continue as normal – this includes collection tours.
"We appreciate our community, and particularly our regular visitors to the MTG and library, will be disappointed at the closure. We will keep everyone updated on expected reopening dates as timing of the remedial works become clearer," said Napier Mayor Kirsten Wise added.
