Barbadoes Street in central Christchurch will re-open on Friday to south-bound traffic.
Civil Defence says the road will help to ease traffic congestion in the earthquake-hit city.
National controller John Hamilton says it balances the public need for better traffic flows, with the need to provide routes for trucks removing demolition materials.
Mr Hamilton says drivers need to be patient and follow speed limits and road signs.
Montreal Street will also hopefully be opened to north-bound traffic on Monday.