German authorities on Sunday slammed Swedish energy giant Vattenfall Europe for waiting several days to declare problems at a nuclear power plant in northern Germany. The Brunsbuettel plant in the state of Schleswig-Holstein had to be temporarily shut down on June 28 because its capacity was overloaded.

Though this was reported, the company failed to inform government authorities that problems occurred when the plant was restarted two days later, a spokesman for the social affairs ministry in Schleswig-Holstein, which is responsible for the region's power plants, said on Sunday.

The ministry called the Brunsbuettel plant on July 1 to ask whether the operation went smoothly and was not informed of any irregularities "though these must have manifested themselves by then," the spokesman said.

He said the ministry was finally informed "at the last moment" on July 6 that the water purification system at the nuclear reactor cooler cut out twice as technicians restarted the reactor.

Vattenfall has also been accused of failing to reveal the full extent of a fire at another nuclear power plant in Schleswig-Holstein on June 28, just hours after the closure of the Brunsbuettel plant.

The blaze at the Kruemmel power plant in Geesthacht, 30 kilometres (20 miles) southeast of Hamburg started when coolant in a large electric power transformer substation ignited due to a short circuit.

It was initially reported that the fire had been isolated from the plant's atomic reactor, but the social affairs ministry said the flames reached the building housing the reactor.

A spokesman for Vattenfall denied a cover-up, insisting: "We kept the public and the authorities fully informed from the very beginning."

The German branch of Friends of the Earth, BUND, has demanded the immediate closure of both plants while the environmentalist Green party has said Vattenfall should lose its licence to operate nuclear power plants in Germany.

The incidents at the two plants come amid a heated national debate about nuclear energy.

Germany has begun a long-term phase-out of its nuclear energy programme and expects to mothball its last plant around 2020.

The plan was approved by the previous Social Democrat and Green government, but Chancellor Angela Merkel's conservatives argue that abandoning nuclear energy will undermine the country's chances of slashing greenhouse gas emissions.

Source: Agence France-Presse