Experts have moved to quash concerns that hundreds of visitors to a Norfolk seal colony are damaging a protected stretch of coastline.

It comes after villagers were alarmed by the vast number of people trampling on Horsey dunes to catch a glimpse of the basking seals and their young.

They fear it may lead to long-term erosion of the area, which forms part of the Winterton to Horsey Dunes- a Site of Special Scientific Interest.

But a reserve manager for Natural England claims the dunes are actually growing in places, and is confident the trampled areas will regenerate over time.

Meanwhile, the Environment Agency guaranteed Horsey's concrete sea defences were in good condition and in no threat of deteriorating.

The beach at Horsey is currently under a two-month voluntary closure to help protect the seals. It means people are allowed on the beach, but it is preferred they watch the animals from a distance by standing behind a roped fence on top of the dunes.

Rick Southwood, Natural England senior reserve manager for the Broads, said: 'There is nobody more concerned about the dunes than Natural England and the Environment Agency. 'We will keep an eye on things and if it becomes eroded or damaged we will put the necessary resources in place to address the problem.

'We don't encourage people to trample on the dunes but we feel it is not having a major impact because there is a concrete defence underneath.

'By the summer the grass will have grown back in areas where it has been trampled. In places we have also seen sand building up.

'It is a balancing act. We have to look after the interests of the seals, the people and the coastline.'

The Horsey seal population has escalated from a mere 10 in 2003 to more than a 1,000 this year.

Currently, more than 80 volunteers are on hand at the beach to give advice to people when visiting the seals. Jack Payne, a parish councillor for Horsey, said some residents are concerned about people wearing away the sand dunes.

He said: 'We see 5,000 people every week going down to see the seals.

'They have put a voluntary closure of the beach in place, but they cannot close it because it is a right of way.

'Now they have opened up the dunes for people to walk on - we feel thousands of people are risking the lives of the whole community by walking on there and wearing it away.'

Sophie Fallon, the Environment Agency's operations delivery team leader for North Norfolk, advised people to stay on the side of the fence and not to disturb the seals.

In 2007, the Environment Agency installed two viewing platforms and wooden steps up the dunes to accommodate visitors to the site.