An emergency inspection was carried out by Northumberland County Council last Thursday after damage was seen.
A council spokesman said: “The Old Bridge is a historic structure and there is inevitably some decay and wear and tear, particularly in the tidal water zone.
“There has been a small area of damage identified at the end of one pier this week that requires attention to prevent further damage over the winter period and we therefore put in place immediate arrangements for a detailed inspection which needed the use of an under-bridge inspection vehicle.
“This will allow us to plan and carry out a repair in the coming weeks, which will include gaining consent from Historic England.
“We understand that people may be concerned about the external appearance of some parts of the bridge, however we can provide reassurance that there is no risk to its overall structural integrity and the damage identified at the pier does not pose any public safety issues.
“The council carries out regular inspections to check for any significant changes in condition. Plans are also in place to carry out more significant restoration work over the next few years to secure the long-term future of the iconic bridge.”
The Grade I listed stone structure was built between 1611 and 1624.