Torrential rains that lashed South Korea for a fourth day on Saturday kept nearly 3,000 people from returning to their homes, while livestock were stranded up to the neck in rising waters as the death toll reached four with two missing, authorities said.

Rain will last until Monday in some areas, weather officials said, urging extreme caution against the risk of landslides and flooding, with warnings across most of the nation.

By 6 am on Saturday, 2,816 people were still out of their homes, the interior ministry said, from a total of more than 7,000 evacuated during the prior days of heavy rain, in which four have died and two are missing.

Rainfall since Wednesday reached a record of more than 500 mm (20 inches) at Seosan, in the South Chungcheong province south of the capital, Seoul, it added.

Elsewhere in the province cows were desperately trying to keep their heads above water after sheds and stables flooded.

The tally of water-damaged structures stood at more than 641 buildings, 388 roads and 59 farms, the ministry said.

Rains were also expected in neighbouring North Korea.

From Sunday to Tuesday 150 mm to 200 mm (6 inches to 8 inches) of rain could fall in some northern areas, rising to 300 mm (12 inches) in some remote regions, the weather agency said, according to state newspaper Rodong Sinmun.