Work on the bridge by English Heritage will see specially-made scaffolding surrounding the bridge, which was built in 1779.
The work had initially been due to start this Spring and will see repairs to cracking on the bridge, caused by ground movements during its lifetime.
People in the town are being invited to find out more at an information session at Number Nine on the Wharfage on August 8 between 4pm and 7pm.
Councillor Nicola Lowery said: “This is the beginning of a fascinating conservation project to renovate one of our most important historical assets. Contractor Taziker Industrial Ltd has an impressive record in working with historic structures and am delighted that investment is being made by English Heritage into the World Heritage Site”.