Investigation works are being carried out on the Mayflower Steps after a routine inspection found some damage to the steps and neighbouring wall.
The steps have been closed off to enable structural engineers to look at what is causing cracking before a schedule of works is drawn up to carry outrepairs.
The inspection was part of a planned programme to review the steps as well as the area around the pier on the Barbican ahead of public realm improvement works for Mayflower 2020.
It is believed the damage has been caused by tidal lag which has caused stress and movement in the historic structure on the Barbican, which is close to the site where the Mayflower sailed from in 1620.
Councillor Mark Lowry, Cabinet Member for Finance, who has responsibility for land and property, said: “We have been made aware of a problem and are taking prompt action to ensure that this sorted as soon as possible.
“We take the safeguarding of Plymouth’s historic assets very seriously and will be ensuring this is repaired quickly and to a high standard.”
These steps and attached pier are grade II listed and are part of the Barbican Conservation Area.
An historic environment specialist will be working alongside the structural engineers, the council’s assets team and a Westcountry heritage stonemason company to ensure the work takes into account their historic value.
Further investigations will take place over the coming weeks which will involve some scaffolding being erected on the seaward side.
Councillor Lowry added: “It makes sense to this now. We have identified a problem, we’re getting a solution sorted and need a period of good weather to progress this. It’s going to be an unusual project as much of the work can only take place on a low tide.”