One of the buildings in Lyttelton damaged in the powerful earthquake on Tuesday was the historic Timeball Station.
The Historic Places Trust describes the building as one of the few of its kind left in the world.
From 1876 to 1934 a ball dropped from its mast on its stone tower, signalling the time to ships in Lyttelton Harbour, the Trust's website says.
Visual time signals were necessary to correct ships' chronometers and ensure accurate navigation.
The timeball apparatus came from German firm Siemens Bros, and the astronomical clock from Edward Dent & Co. of London, who had made the Big Ben clock.
Use of the timeball was discontinued in 1934 when it was replaced by radio signals.
The flags, which predated the Timeball Station, were used on the flagstaff nearby to signal to ships and to communicate shipping advice to the town.
A fine example of Victorian technology, the Timeball Station is today one of only five in the world known to be still in working order. It is a rare piece of maritime history, fabulously restored and boasting spectacular views over Lyttelton Harbour.