Homes are at risk of being swallowed up by the sea unless a rock wall is built to protect them in the next 50 years.

Between ten and 30 metres of cliff are predicted to erode away in the next half century, raising fears about threats to property, amenities, wildlife and ancient structures.

Lewes District Council commissioned consultants to develop a coastal defence strategy plan for the area between Saltdean and Newhaven until 2050.

The report says existing sea defences needs to be properly maintained and new defences will be needed in some unprotected areas to protect assets.

However, the A259 coastal road is not thought to be at risk.

The report says: "The constant erosion and abrasion from the sea of the undefended frontage of the chalk cliffs between Saltdean and Newhaven will inevitably result in further losses of cliff edge of varying magnitudes over a period of time."

An area from Telscombe Cliffs to Fairlight Avenue is under threat from crumbling cliffs and will need to be protected at a cost of £445,000 to save assets including homes and The Esplanade, it says.

During the wettest winter since records began, there have been cliff falls at Brighton Marina, some near properties, at Telscombe Cliffs, Peacehaven and West Beach in Newhaven.

Lindsay Frost, director of planning and environment at the council, said it was competing with other local authorities for Government cash for defences and needed to weigh up the cost and benefits.

He said: "The analysis concluded a rock revetment was needed to protect some cliff-top properties. In the worst case scenario, the houses will be rendered useless if the road is lost to the sea because they will be inaccessible."

Mr Frost said the council had 50 years to consider how areas should be protected and would probably apply for money to build the revetment in 2013.

It would cost about £1.86 million for a rolling programme of maintenance of existing defences.

Telscombe councillor David Neighbour said councils had to weigh up potential threats to property with the demands of conservationists, who did not want the forces of nature to be interfered with.

Public meetings to discuss the coastal defence strategy will be held at Meeching Hall in Newhaven on Tuesday between 2.30pm and 8pm and at Telscombe Civic Centre on May 16 at 7pm.

The public are invited to send their comments by June 22, to Coast Defence Consultation, Lewes District Council, PO Box 2707, Lewes, BN7 1DW.