The government has raised the heatwave crisis alert to the third highest level in a four-tier scheme in view of a higher number of patients suffering from heat-related illnesses compared to last year.

The interior ministry said it raised the alert from "attention" to "caution" as of noon Wednesday, in line with protocol calling for the second tier to be activated when the highest “feels like” temperature of the day is forecast at 33 degrees Celsius or higher for at least three days in 18 or more regions nationwide.

The ministry said that particular condition has not been met but it raised the alert anyway in consideration of an on-year hike in patients of heat-related illnesses.

According to data by the Korea Disease Control and Prevention Agency, there were 149 such patients as of June 19, compared to 104 during the same period last year.

The ministry has also ordered other agencies and provincial governments to step up related measures such as renovating heat shelters and educating the public on ways to cope with hot weather.

It also promised to inspect policies to minimize effects on those especially vulnerable to heat including outdoor construction workers, seniors living alone and elderly farmers.