Parents have started a petition to save a playground built to mark the Aberfan disaster from being turned into a housing development.
Mothers living near the park are angry at the plans to develop it
Coventry Park in Merthyr Vale was built following the 1966 tragedy, in which 144 people died.
But plans are being considered to use the space to build 11 bungalows on.
Local parents are campaigning to stop the proposals, saying they are an insult to the memories of the dead.
The park was created two years after the disaster by donations from the people of Coventry and was opened by the city's mayor.
Carol Jenkins, who lives near the park said that she was shocked when she received a letter informing her of the proposals.
"I couldn't believe it," she said.
"It is an absolute insult and completely and utterly insensitive.
"This park was given to us by the people of Coventry in memory to those children who perished in the disaster.
"There are many survivors who will be appalled that they want to do this."
The council say the playground is now 'dilapidated'
She said that although the park had become run-down over the years, it was still popular with local children.
"In the summer holidays, the park is the place where the children go.
"The council tell us that it has become derelict and is not used anymore, but that is simply not the case.
"On a hot day in the summer, there are always lots of children playing there."
Ms Jenkins and four other mothers have set up a group campaigning to save the park from development.
"We have had a lot of support and not just from local people but from people not from the area," she said.
"And we have started a petition which has already been signed by about 400 people which we are going to hand in to Merthyr Council on Thursday to show our objection to the plans.
"It is a huge insult to everyone that they are even considering it," she added.
A spokeswoman for Merthyr Council said that the site was under consideration for disposal due to its dilapidated state.
Signs have been put up in windows against the proposals
"The land was originally the location of a school and has not been utilised as a playground for a considerable period of time, it is currently derelict.
"The future of the site has been under consideration for disposal, possibly for residential development, with the aim of bringing the site back into productive use and improving the quality and choice of housing stock in the renewal area," she said.
The council has been working with Merthyr Tydfil Housing Association to try and improve housing in the area.
Karen Dusgate, chief executive officer for the association said: "In recent years the Coventry Playground has become less used and increasingly dilapidated.
"The association was ask to consider if the Coventry Playground could begin to meet some of the housing needs of the local community, in particular the needs of older people for bungalows.
"We are very aware and very sensitive to the memories of the community and the donation of the play area to the community by the people of Coventry.
"For this reason we approached the local Communities First Partnership Board to present the idea and suggested that a consultation exercise is undertaken in order to gauge how people feel about the proposed development of the site."
She said that letters had been sent out to homes nearby about the proposals but said it was "very early days".
The Aberfan community, near Merthyr Tydfil, was devastated on 21 October 1966 after a slagheap overlooking the area became unstable.
Tonnes of waste slid down the mountainside toward the village destroying a farm in its path and killing the occupants.
Children at Pantglas Junior School had just returned from singing hymns at their morning assembly.
But the slide engulfed the building, killing 116 children and five of their teachers.
The slurry also engulfed 20 houses before coming to a halt.