The sea wall at Walton on the Naze helps to protect a wetland site of designated international importance under the Ramsar Convention.
The repair work will ensure the wall remains an effective flood defence for years to come and prevent any further deterioration.
Starting later this month, a section of the tidal defence embankment will be refurbished over a 3 month period.
The project will see the renovation of a 1.7 kilometre stretch of the embankment, running north up the coast from Foundry Lane.
The work is being carried out by civil engineering contractors Breheny and will take place on the crest and seaward sides of the embankment.
Work is due to begin in the week commencing 9 October 2017 and normal working hours will be from 7:30am to 5pm, Monday to Friday.
Kerry Bentley, Asset Performance Officer for the Environment Agency, said:
This is very important work and will ensure the sea wall can continue to provide an effective level of protection in the area for years to come.
The damaged sections of existing sea wall will be removed and new sections will be added.
The old blocks will be placed at the toe of the sea wall as habitat and to help reduce wave impact.
In order to ensure the safe delivery of these works we will need to redirect short sections of the footpath to the rear of the wall.