Hungarian Prime Minister Péter Magyar has accused his predecessor Viktor Orbán's government of failing to prepare the country's energy system for the challenges exposed by the ongoing drought and heatwave, as low water levels and high temperatures have put pressure on the Paks nuclear power plant.

Magyar said the former government had been aware for years that Hungary's electricity system was under strain but had failed to address the risks.

"Viktor Orbán and his team knew in 2022 that the Hungarian energy system was reaching its final days and was on the verge of collapse. And yet they did nothing," Magyar wrote in a Facebook post.

He referred to a 2022 government proposal which, he said, warned that the electricity system was becoming unsustainable due to rising demand and insufficient investment in generation capacity.

"The maintenance of the system's balance will lead to its final days, with costs reaching unprecedented levels (from HUF50bn to HUF392bn per year), and without drastic measures, it will become unsustainable within a few months," Magyar quoted from the document.

The prime minister also criticised the government's reliance on nuclear power from the Paks plant while expanding energy-intensive industrial projects, including battery factories.

"They knew exactly that, as they calculated that they promised more electricity to large industrial (battery industry) investments than the system could safely supply," he said.

Hungary has been hit by an extended heatwave and drought, affecting agriculture, water supplies and energy production. The government said on August 4 it had extended a third-degree heat alert until August 7 as forecasts showed average daily temperatures would remain above 27 degrees Celsius.

High temperatures and low river levels have created challenges for thermal and nuclear power plants that rely on river water for cooling. The four operating reactors at the Paks nuclear plant, Hungary's only nuclear power station, are located on the Danube and have previously faced restrictions during periods of exceptionally warm weather and low river flows.

The government has said the country's energy supply remains stable. In a separate Facebook post, Magyar said the country's Defence Work Group had concluded that "the energy and water supply in our country is stable" and that "from now on, there is no need for voluntary consumption reduction."

"The Paks turbine produces stably. The Danube water level will rise by 20-30 centimetres on an interim basis due to the rainfall in Austria," he wrote.

Hungary's former government pushed to expand nuclear capacity through the planned Paks II project, being built with Russian technology and financing, while also increasing solar power generation.

However, Magyar said the government had failed to build sufficient flexible generation capacity or modernise the electricity network.

"In 2022, no new power generation capacity capable of being built at any time was constructed for more than ten years," he said. "The replacement or development of the old units was delayed, and neither the grid nor the storage system was able to keep up with the rapid spread of solar power. The construction of wind farms was hindered."