Erica Maliki and her family were burying her father-in-law at Springvale Cemetery when she was told the price per burial plot had increased because of the carbon tax.
Her father-in-law died on June 30, the day before the carbon tax was introduced, and was buried early last week.
"I thought to myself, 'What carbon could possibly be used by putting a man in a grave?'" Ms Maliki said.
"All they did was put the dirt back in. How can they charge us a carbon tax for burying someone?"
Ms Maliki's son Zaid said the cemetery's receptionist told his sister-in-law "even the dead don't escape the carbon tax".
"We are pretty upset… that comment was a kick in the guts," he said.
Climate Change Minister Greg Combet said it would be "reprehensible" if any cemetery was taking advantage of grieving families by overcharging them for funerals.
The ACCC, which is investigating three companies accused of blaming the tax for price hikes, said it would be willing to investigate the claims.