Parents at two schools in south Dublin have said they are extremely disappointed that a congregation of nuns has sold land attached to the schools to a developer for a reported €13 million.

The land - 5.4 acres - was previously used by students attending Our Lady's Grove Primary School and Jesus and Mary Secondary School in Goatstown.

The sale comes just two weeks after the Christian Brothers sold playing fields attached to another south Dublin school, Clonkeen College, for a sum of €10m.

Both sites are zoned for housing.

The Goatstown site is suitable for up to 80 houses and apartments.

RTÉ News has established that the land in question, called Roebuck Grove, was sold to the congregation in 1963 by the State's Land Commission.

Historians and former Land Commission employees say it would have been unusual for the Commission to have dealt with land so close to Dublin city.

Legal documents state that the land was sold for what is referred to as a "consideration". The documents do not mention the actual price paid.

The Sisters of Jesus and Mary have told RTÉ News that they purchased the lands in 1963 at market value, with their own finance as well as some assistance provided from the congregation in the UK.

One parent at the school said parents were really angry that they had not been not consulted.

Lisa Ryan said they will continue their campaign to prevent the land being developed. 

Ms Ryan said while the sisters had done a lot of good work in the past, this was now their legacy and what they would be remembered for.

She added that parents were calling on Dun Laoghaire Rathdown Council to overturn the residential zoning of this land.

She said the State had responsibility to ensure that green spaces attached to public schools was not sold off and developed. "If the State didn't zone these lands as residential then this wouldn't be happening," she said.

Roebuck Grove is also the birthplace of the Irish stained glass artist Evie Hone. She was born in the house on the land in 1894.