Slope stabilisation works will be carried out 83 kilometres west of Grafton over the next three weeks.
Traffic on the highway has been reduced to one lane for safety reasons since March after heavy rainfall in the wake of tropical cyclone Debbie.
Roads and Maritime Services will carry out slope stabilisation so the road can be fully re-opened. One lane will remain closed while work takes place and there will be a three-metre width restriction due to the placement of one metre high barriers.
Vehicles more than three metres wide with a clearance of more than 1.07 metres high may be eligible to travel via permit, subject to consideration.
Motorists are to expect delays of up to 10 minutes.