The Law Courts building in Sydney will be shut on Monday after a faulty sprinkler caused extensive water damage to at least four floors of the court complex, including the Supreme Court registry.

NSW Fire and Rescue workers were called to the Phillip Street courts complex, home to the Supreme and Federal Courts, around midday on Sunday to help remove water from the foyer and another three floors of the building.

A faulty sprinkler caused water damage to at least four floors of the Law Courts building. Credit:Anna Kucera

It is believed the flooding started on level six, which houses Supreme Court administrative staff, and was caused by a damaged sprinkler head and a burst pipe.

The three floors below, including the Supreme Court registries on levels four and five, were also flooded. It is not yet clear when the complex will reopen.