Lyttelton residents are worried the delay on the Timeball Station rebuild may cause the project to be abandoned altogether.
Work to restore the station has been postponed due to nearby road works which will block access until at least the end of the year.
Heritage New Zealand was set to start the rebuild this month but re-scheduled to avoid conflict with road works on Sumner Rd and Reserve Tce.
But Lyttelton Community Association president Ken Maynard said residents are worried that the delay may mean the restoration work is forgotten.
"If they put it on the back burner, we're worried the project is going to be dropped altogether."
Mr Maynard has been in contact with Heritage New Zealand who assured him they were not stalling with a view to drop it, and it was doing restoration on the equipment in the background.
Heritage New Zealand has not been able to indicate an exact date as to when work will begin, as it needs to know when the site can be accessed.
While the work on Reserve Tce is scheduled to be completed by the end of this year, work on the Lyttelton end of Sumner Rd is currently scheduled to continue well into 2017.
Heritage New Zealand acting southern region general manager Frank van der Heijden said repairs can only be done in spring or summer as the stone masonry work uses traditional lime mortar and render, which could only be set properly outside of winter.
Mr Maynard said road works are a priority, but he wants a date so residents can be assured work will go ahead.
"What I can't understand is why won't they say when they're going to start? If they can't start this spring due to the roads, why can't they say it will be started by October 2017? It's a long way off but at least it's a date."
The station was constructed in 1876 as a time keeping device for ships in the harbour, but was badly damaged during the September 4, 2010 and February 22, 2011 earthquakes.
Mr Maynard said the category one heritage building is a crucial part of Lyttelton's identity and a major tourist attraction for the area.