Over 830,000 farm animals, including 786,512 chickens, have been killed since 20 July, when midday temperatures began hovering above 33 C in most parts of the country, according to the Ministry of Food, Agriculture, Forestry and Fisheries, reports YonhapNewsAgency.

The dead animals include 40,780 ducks and 336 pigs.

Such damages are often caused by power outages that can halt the ventilation and cooling systems at farms.

The country was forced to issue power shortage warnings for two consecutive days this week as the sweltering weather pushed up its energy consumption to new highs, driving down its electricity levels to what officials called "dangerous levels" of less than 3 million kilowatts.

"The number of animals killed may actually be greater, pending on a more thorough survey," a ministry official said, noting damages may also grow from the continuing heat wave.

The country is also experiencing its longest streak of so-called tropical nights, where overnight temperatures stay above 25 C.