Human skeletons are being unearthed on an island in New York, after years of storms eroding the shorelines.

More than 170 bones were recovered from Hart Island cemetery on Monday (April 23), where more than one million unclaimed New Yorkers are buried, reported CBS New York on Tuesday.

"Entire skeletons are sort of falling out of the hill onto the beach, and then they're washed away with the tide," advocate Melinda Hunt of the Hart Island Project told the news channel.

The island is a public cemetery for people who cannot pay for their own burial, who have not been identified, or for those whose family or relatives cannot be reached.

The island's first burial records date back to as early as 1881, according to the New York City's official website.

Run by the Department of Correction, the island requires visitors to make an appointment in advance.

According to Ms Hunt, the prison officers running the island are aware of the exposed remains and have even nicknamed the island "Bones Beach".

New York City Council member Mark Levine told CBS New York that he is trying to transfer control of the island to the Department of Parks and Recreation instead.

"Why in the world would an agency that's managing our jails have anything to do with this island?" Mr Levine was quoted as saying.

On the island, red flags were spotted marking areas where skeletons have been unearthed. The remains will be reburied by prisoners, reported CBS New York.

"It's simply wrong that people who are neglected in life, who were marginalised in life in the city are now getting the same treatment in this burial ground," said Mr Levine.