West Dorset District Council has received full financial approval from the Environment Agency for a £19.5 million coastal protection project at Lyme Regis.
The scheme, which is the fourth and final phase of works in the area, is designed to protect 480 properties, 900 metres of Charmouth Road and Church Street and mains utilities pipes and cables that are in danger as a result of coastal erosion.
It will involve the construction of 390m of new seawall and slope stabilisation works to the cliffs behind it.
Leader of West Dorset District Council, councillor Robert Gould, said that the decision was "great news".
"[This work] will protect the eastern side of the town where housing and the main road into the town would otherwise be lost due to the effects of coastal erosion," he said.
Preliminary work on the site has begun, although the bulk of the project is to be completed during 2013 and 2014.