Opponents say the plans would cause disruption to the path to the cemetery
People who lost loved ones in the 1966 Aberfan disaster are fighting proposals to build houses near the cemetery where they are buried.
Parents who lost children are among hundreds to sign a petition opposing plans for 19 homes near the entrance.
A coal tip slid on to the village school near Merthyr 43 years ago, killing 144, including 116 children.
The developer said the site does not adjoin the cemetery and the houses would have no impact upon it.
Gaynor Madgwick, who was eight years old when she was rescued from the disaster, said the development would affect people visiting the cemetery.
"It's a very insensitive area to put 19 private houses and a time of year when people are finding it hard [close to the anniversary on 21 October]," she said.
"It's added stress to the residents and the bereaved. It would cause disruption to the pathway to the cemetery when people want to grieve in private."
She said more than 830 people had signed a petition opposing the development, including 82 of the bereaved.
"You will not see any cemetery where houses are built right next to it. It's a place of peace," she said.
"People come from all around the world to visit that cemetery."
Merthyr council officers have recommended that the plan is refused when considered at a full council meeting on Wednesday.
I wouldn't do anything that I feel would affect the cemetery in any way
They said the site was outside the settlement boundary and considered to be unsympathetic and uncharacteristic of the development pattern of the village.
They also say the houses would "substantially alter and seriously harm" the setting: the cemetery has been designated a Grade II historic park.
But the developer, Brett Hughes of Aberfan, said the application site did not adjoin the cemetery and was separated by a large area of land and track.
He said: "I know there's a minority of people who are against it but the site is about 200m from the cemetery so no actual views can be exchanged."
He added: "There's a major shortage of housing in Aberfan/Merthyr Vale.
"It's not going to affect the cemetery and is going to improve housing and that was the decision of the planning committee three weeks ago when it was approved."
He said a petition in support of the application had also been submitted.
"I've got family buried there myself, not through the disaster, but I wouldn't do anything that I feel would affect the cemetery in any way," he said.