"You know my view about it. We do not know enough about the reaction of this material," he told reporters when asked on his view on building the plant.
Dr Mahathir said the radiation leaking from the stricken Japanese nuclear power plant due to the tsunami after the 9.0-magnitude earthquake seemed to lend support for his concern.
"Once it is activated, it becomes radioactive. People do not know how to get rid of the waste," he said.
He noted that during his premiership the government had decided on four fuel strategies namely oil, gas, coal, hydro, and "nuclear was not included."
"We have bad experience already with nuclear. I don't know whether people are aware about it or not," he said.
Asked whether he would advise Prime Minister Datuk Seri Najib Tun Razak not to have nuclear power plant, Dr Mahathir said, "I'm not an advisor. That is why I use my blog."
Malaysia plans to build two nuclear power plants that will generate 1,000 megawatts each with the first plant ready for operation in 2021 and the second plant, a year later.
It was part of the overall long-term plan to balance energy suppl