ATHENS (Reuters) -On Greece's popular island of Paros, a protest by residents demanding space and free access to its sandy beaches has led to a growing nationwide movement against the expansion of pricey sunbeds rented out by private companies.

The protests, dubbed by media the 'Towel Movement', have quickly spread from Paros to the nearby island of Naxos and to other holiday spots at the north and the south of the country.

"The locals enjoy the peacefulness here, so we do not want it [the beach] to be taken up by businesses who care about the money, and not about nature and the vibe," said Ronit Nesher, a 53-year-old Paros resident.

"We do not want the beach to be occupied by umbrellas and huge, you know, really humongous beds that have nothing to do with the simplicity of the island."

Beaches are public in Greece, a country receiving millions of tourists every year, mainly in the summer, its top tourism season. However, an increasing number of businesses have received licenses to rent out sun beds and umbrellas which they set up along a stretch of beach.

Protesters say that prices for two loungers and an umbrella can often top 100 euros for a day, and in many cases businesses expand well beyond the agreed area of beach, leaving little room for those who want to lay a towel and sunbathe for free.

"We come here peacefully... we just want to let you know that we are trying to reclaim our right to free access to our beaches," said one of the protesters through a loudspeaker as he walked through sun loungers at the Marcello beach in Paros.

A prosecutor has launched an investigation into Paros' case.

In Naxos, more than 5,000 people have joined the Facebook group "Save the beaches of Naxos now!", which has also filed a legal complaint.

"The beaches were so full of this furniture ... that many people who didn't want to sit on a bed or in a chair, had no other space to sit anymore," said Eleni Andrianopoulou, 47, one of the group's organisers.

Greece has a 16,000 kilometre long coastline and hundreds of beaches where companies hire sunbeds. The country emerged from a debt crisis five years ago and relies heavily on tourism for economic recovery.

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(Reporting by Renee Maltezou and Deborah Kyvrikosaios; Editing by Alexandra Hudson)