Iran's first nuclear power plant has started adding electricity to the national grid, coming on stream last night after years of delays.

"The Bushehr nuclear power plant joined the national grid on Saturday at 23.29pm (7.29pm Irish time) with the power of around 60 megawatts," the ISNA news agency reported.

Hamid-Khadem Qaemi, spokesman for the Atomic Energy Organisation, told Iran's Arabic language TV station al-Alam the plant would be officially inaugurated by 12 September by which time it would be operating at 40% capacity.

The 1,000-megawatt plant on the Gulf coast is the first of what Iran hopes will become a network of nuclear facilities that will reduce its reliance on its abundant fossil fuels.

Started by Germany's Siemens in the 1970s before Iran's Islamic revolution, the project was later taken over by Russian engineers and has since suffered a series of delays.

The West fears Iran's nuclear programme is aimed at making atomic weapons, which Tehran denies.

Experts say firing up the Bushehr plant will not bring Iran any closer to building a nuclear bomb because Russia will supply the enriched uranium for the reactor and take away spent fuel that could be used to make weapons-grade plutonium.