The defences, which are a sheet piled flood wall, reduce the risk of flooding to people and 4305 properties in Purfleet.
Damaged sections of concrete blocks, which protect the coast from erosion, will be repaired to restore them to their original condition.
Graham Verrier, Environment Agency flood risk manager said:
Whilst the existing defences were damaged during the 2013 tidal surge, they still did their job of reducing the risk of flooding to people and properties in Purfleet.
However, we need to be confident that potential flooding can be withstood for many years to come which is why this work is so important.
The work, which will involve a floating barge, is expected to take 3 months to complete. The existing standard of flood protection will be maintained throughout the works.