The Main Road causeway linking the seaside suburb of Sumner to Christchurch is being closed for six months while repairs are carried out.
A new sea wall will also be built as the earthquake-damaged road is reconstructed.
Stronger Christchurch Infrastructure Rebuild Team (SCIRT) says the road will close from 9.30am on Monday.
General manager Duncan Gibbs says shutting down the road shortens the construction time frame by two months and is safer for workers and road users.
A detour will be in place on McCormacks Bay Road.