Hungary is planning to allow the temperature limit for a section of the Danube which receives cooling water from the Paks nuclear power plant to be exceeded for security of supply reasons, the energy ministry said in a statement on Friday.

The plant's four reactors operate by using the water of the Danube to cool its operations. Currently, according to the regulation, the river cannot receive water if its temperature exceeds 30 degree Celsius, in which case the operator must cut output and wait for the river to cool below the limit.

"Due to climate change, weather conditions may increasingly lead to the limit being reached in summer, especially at low water levels," the statement read.

The energy ministry's proposed plan would keep this limit in place but would allow the operator to exceed it on a case-by-case basis with the permission of the minister of energy, if this is unavoidable for security of supply.

"The curtailment of Paks' output could directly jeopardise the smooth supply of domestic consumers in a tight energy market," the statement read.

"In addition to environmental considerations, it may therefore be justified to exceed the limit value on a case-by-case basis if this is unavoidable for security of supply."

The Paks plant has four Russian-built VVER 440 reactors with a combined capacity of about 2,000 megawatts. The reactors became operational between 1982 and 1987 and are scheduled to be retired in 2032-2037.

Hungary plans to expand the plant, with Russia's Rosatom building two VVER reactors with a capacity of 1.2 gigawatts each, in addition to the currently working four reactors.