Parents have presented a petition to oppose plans to turn a playground built to mark the Aberfan disaster 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 October 1966 tragedy in which 116 children and 28 adults died.
Proposals are being considered to build 11 bungalows on the space.
Merthyr Council stressed that "due consideration" will be given to those affected by the proposals.
The playground was built at a school with money raised by the people of Coventry.
The school later closed and the playground was refurbished in the early 1990s by the council.
A council spokeswoman said: "Recently there has been a problem with anti-social behaviour from youths congregating in the playground that has caused problems for those living nearby.
The council says the playground is now 'dilapidated'
"Consequently, the project to redevelop the site has now been identified as part of the regeneration process for the area."
The council said the main aim of the scheme would be to provide a development including bungalows, but that it would also include a lasting memorial or a small play area.
The park was created in 1968 by donations from the people of Coventry and opened by the city's mayor.
Carol Jenkins, who lives near the park, 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.
Ms Jenkins and four other mothers set up a group campaigning to save the park from development and a petition with more than 400 signatures was collected.
She said that although the park had become rundown over the years, it was still popular with local children.