Heat kills 16 in South Korea this summer: interior ministry

South Korea's summer heat has killed 16 people so far this year, the interior ministry said Tuesday, as the nation swelters in a wave of searing weather.

Between May 15 and and August 2 a total of 2,025 people have suffered heat-related illnesses, of which 16 people have died, a ministry statement said.

South Korea's heat record has been broken three times over the past week, with the latest all-time high set at 42.5C in the city of Yangsan on Sunday.

The whole of Seoul was under the highest-level "severe heatwave warning" alert Tuesday, with temperatures forecast to soar again close to 40C.

"Extreme, life-threatening heat is forecast," the weather agency said in a statement Tuesday.