Severe thunderstorms hit Hungary on Monday forcing the closure of the main international airport in the capital Budapest after debris had been blown across the runways.

The departures hall in Terminal 2A was partially flooded and the building was evacuated but no injuries were reported, the airport said in a statement.

"All passenger check-in is taking place at Terminal 2B. The storm has also affected the surrounding roads, please be advised of any traffic changes before departure," airport authorities said, adding that damage assessment is underway.

According to Flightradar, several flights scheduled to arrive in Budapest had to be diverted and land elsewhere.

A Ryanair flight from Prague was diverted to Bratislava and the airport said several aircraft have been circling the airport waiting for a landing slot. They warned that flight cancellations cannot be ruled out.

The storm also affected the national railway network with MÁVINFORM reporting longer journey times on the North Balaton line due to overhead line faults and replacement bus services in place between Balatonfüred and Szabadbattyán.

In a statement, MÁVINFORM said that gale-force winds of 150-170 km/h on the northern shore of Lake Balaton had blown down the overhead line, while on the southern shore trees had fallen onto the track, damaging power lines.

They added that the National Emergency Centre had immediately deployed around 50 to 60 buses to ensure passengers could get to their destinations and that experts were working to repair the faults.

The country's meteorological office, the Republic Hydrometeorological Institute of Serbia (RHMZ) issued a severe weather warning on Monday for Belgrade, mountainous areas in the southeast and Vojvodina.

Rain and thunderstorms were forecast, and Bačka and central and northern Banat saw intense storms with hail and strong winds.

Shortly after 2 pm, gale force winds and heavy rain hit Zrenjanin, a correspondent for state television RTS said.

The wind brought down branches from trees and caused minor flooding on some roads. Manholes and drains were clogged with leaves that had been blown by the wind.

At around 2:15 pm, Subotica was hit by a thunderstorm.

RHMZ said that sunny, warm weather is expected to return to most parts of the country by the end of the day, with thunderstorms most likely to continue in the north and west.

A strong storm lashed the Croatian coast and moved inland, reaching the country's east.

The State Hydrometeorological Institute (DHMZ) issued its highest red warning level for the Osijek region, which indicates extremely dangerous weather.

A message has also been sent to residents in the area, warning of stormy and hurricane-force winds.

The Vukovar-Srijem Police Department received 30 reports of damage caused by the storm but no injuries.

While the national electric grid warned of the possibility of reduced voltage in some parts of Županja.

And rainfall that hit Slovenia overnight has eased but is expected to intensify again by the evening.

The national meteorological service Arso issued an orange warning for the entire country for Monday due to possible heavy rains with hail, gusts of wind and lightning.

A new, more pronounced wave of precipitation is expected to hit the country on Tuesday night, when local storms are again possible.

The heaviest rainfall is expected to be in the west and northern areas.