Works starts on a new water main under Collins Street in the Melbourne CBD on Monday, and some disruption to the busy bike route will result.
However the street will not be blocked and bikes can get through under the control of traffic management.
The work will start at Elizabeth Street and proceed along the south side of the street towards Swanston Street.
The new main will be placed under the road where car parking might otherwise be located.
Work will take place between 7am and 6pm Monday to Friday.
The current main dates from 1915 and is reaching the end of its operational life.
Trams will not be affected by the work.