The Old Waimakariri Bridge just north of Christchurch is closed due to high river levels on Wednesday.
Christchurch City Council says it is likely the bridge will remain closed for several days following heavy rain upstream.
The council is warning cyclists not to use the main Waimakariri Bridge on the motorway on State Highway 1.
Cyclists will be ferried across the motorway bridge, with collection points on Main North Road and Marshland Road.
