Iran's Russian-built nuclear power plant has experienced technical problems with its generator and experts are working to resolve the issue, Tehran's envoy to Moscow said on Monday.

Ambassador Mahmoud Reza Sajjadi said there was "absolutely no link" between this problem at the Bushehr plant – which was shut down when UN nuclear inspectors went there in mid-May – and a powerful earthquake that shook the region two months ago.

He spoke a few days after Arab Gulf states sought reassurances from Iran at a UN nuclear agency meeting over the safety of its only nuclear energy plant, which is located in an earthquake-prone area.

The facility on Iran's Gulf coast is a growing worry for nearby countries: if radiation ever does escape it could be blown over the Gulf to Qatar's capital Doha and the main oil exporting ports of the United Arab Emirates.

Earlier this year, reports by the UN's International Atomic Energy Agency (IAEA) said Iran had informed inspectors visiting the plant in mid-February and again last month that the plant was shut down but gave no details.

"The one problem in the working of the nuclear power plant at Bushehr occurred with the generator," Sajjadi told a news conference, without saying when it happened. "We are working very closely with Russian specialists to resolve the issue."

Tehran repeatedly has rejected safety concerns about the reactor, which began operations in 2011 after decades of delays. Iran and the Russian company that built Bushehr said it was not affected by the April earthquake.

"There is absolutely no link to the earthquake here. The nuclear power plant is designed to sustain a powerful earthquake," Sajjadi said. Asked whether the plant was online now, he said: "I do not have any current information."

Construction of the 1,000-megawatt plant was begun in 1975 by German company Siemens, and Russian engineers took over in the 1990s.

The West suspects Iran is seeking the capability to develop nuclear weapons behind the facade of an atomic energy program.

But Bushehr is not considered a major proliferation risk by Western states, whose fears are focused on sites where Iran has defied global pressure and Russian-approved UN sanctions by enriching uranium beyond levels needed to fuel power plants.

Iran says its nuclear program is a peaceful bid to generate electricity and to produce medical isotopes.