BEIJING - The operator of a nuclear power plant in southern China has acknowledged possible cracks in fuel tubes but, contradicting Hong Kong authorities, denied that any radiation had leaked out.

"Daya Bay's two reactor units are functioning safely and stably. There has been no radioactive leak," China Guangdong Nuclear Power Group said in a notice posted on its website Tuesday.

However, the notice said that on May 23 technicians detected abnormally high radioactivity in the Daya Bay Nuclear Power Station's systems, which it said may have been due to cracks in fuel tubing.

Washington-based Radio Free Asia first reported a leak at the plant, which the Hong Kong government confirmed on Tuesday.

Daya Bay is located about 50 kilometres (31 miles) north of Hong Kong in China's Guangdong province, and is part-owned and managed by CLP Power, Hong Kong's largest electricity supplier.

The Hong Kong government's statement had said there was a "very small leakage at a fuel rod" that had been completely quarantined.

Radio Free Asia had quoted a "Hong Kong expert source" as saying a large amount of radioactive iodine was released into the air. It said the plant's management had kept the incident secret and only later reported it to authorities in Beijing.

China Guangdong Nuclear Power said the situation was too minor to warrant an international nuclear incident report. CLP had already made a similar statement.