An Argentine woman has been freed after being found naked and chained to a bed in a house where she was held captive for 20 years.

Marisa Almiron, 42, spent decades as a prisoner of her own family after she was locked up by her father 'for having a boyfriend' as a young woman, local media reports.

The extraordinary incarceration has shades of the infamous Josef Fritzl case in Austria that shocked the world in 2008.

The house in the city of Sante Fe in Argentina where Marisa Almiron was locked up for 20 years

Reports say police found Marisa with clear signs of malnutrition, surrounded by her own excrement and that she has been 'psychologically affected' by her 20-year confinement.

She was kept locked up at a house in the city of Venado Tuerto in the northern Argentine province of Santa Fe and is now being treated at hospital.

According to reports, Marisa's father first imprisoned her as a young woman.

After eight years, when the father died, her brother Mario is said to have continued the practice and has allegedly kept her chained up for the past 12 years.

There are six siblings in total and all of them knew what was happening under the family roof, according to official sources.

The victim was finally rescued thanks to a concerned neighbour, who told local media:

'My home became a living hell because of the screams I could hear through the walls. That woman suffered a lot of bad things.'

The neighbour said that she had been reporting the situation for years, but police never acted on her warnings.

The case is a reminder of 'monster' Josef Fritzl (left) who kept his daughter Elisabeth Fritzl prisoner in his Austria home for 24 years

When the authorities did arrive, Mario would not let them in and told them they needed a warrant.

He reportedly said that he only kept his sister chained to her bed because she had 'psychological problems'.

According to the neighbour: 'The sisters threatened me and told me to leave things be.

'I now see the man (Mario) freely walking around as though nothing has happened. This is incredible and places some of us (neighbours) in danger.'

So far, Mario has not been arrested. The investigation continues.