At least 44 have died from the worst floods that hit Serbia and Bosnia in more than a century over the weekend. Four days of heavy rainfall had triggered landslides forcing thousands to flee their homes as mud covered villages and roads. Rising flood waters are likewise threatening the power plants in the region.

Authorities expect the death toll to rise in the coming days once the flood waters have receded.

"The situation is catastrophic," Serbian Prime Minister Aleksandar Vucic said.

Devastation was widespread anywhere one looks.

"It looks like a tsunami and earthquake occurred at once. Water carries everything. Corpses of animals could be seen floating everywhere," Nedeljko Brankovic, one of rescue workers who managed to reach the village of Krupanj in western Serbia after two days, told AFP.

"We found some 50 people gathered in the highest house. They had neither electricity nor drinking water. Telephones did not work. We evacuated them 10 by 10 in a huge boat," Mr Brankovic added.

In Belgrade, capital of Serbia, shelters were erected from the dozens of schools and sport centers for the thousands of displaced evacuees from the disaster zones.

"The water was two metres high in less than an hour," 73-year-old Vojislav Majstorovic, who lives in Obrenovac, said. "We did not have time even to pack basic things. We just ran to the first floor and waved a white sheet to alert rescuers."

The amount of rainfall that struck Serbia and Bosnia in the past three days was good for three months' worth. The flooding and resulting landslides had removed warning signs near landmines which still have weapons that were remnants of the Bosnian War of 1992-95.

Authorities in Serbia are currently racing against time to erect and raise sandbag barriers to protect the perimeter of the Kostolac power plant located east of Belgrade. The plant supplies 20 per cent of the country's electricity needs.

"More and more water is getting closer but for the timebeing the sandbag defence barriers are holding," Dragan Jovanovic, Kostolac general manager, was quoted by Tanjug news agency.

Rains and flood waters have receded on Sunday in Serbia and Bosnia, but authorities said they expect Sava River to rise further.

Serbia's largest power plant, the Nikola Tesla in Obrenovac, is likewise threatened.

Flooding had disrupted Serbian power generation by 40 per cent, forcing the cash-strapped country to boost imports, according to Reuters.

An estimated 95,000 homes are without power.