The Philippines is looking into operating the country's only nuclear power plant, built four decades ago at more than $2 billion but never used, to ensure the long-term supply of clean and cheap electricity, its energy minister said.

The Southeast Asian country is joining more than two dozen other countries looking to add nuclear power to their energy mix, including neighbors Indonesia, Vietnam, Malaysia and Thailand.

Energy Secretary Alfonso Cusi said on Tuesday reviving the mothballed 620-megawatt nuclear plant in Bataan province, northwest of Manila, will require a $1 billion investment.