The government has raised its crisis weather alert level in preparation for heat waves that are forecast to linger for some time.

The Interior Ministry said the four-point crisis alert level was raised from the third-highest "caution" to the second-highest "alert" as of 10:00 a.m. on Tuesday in a proactive step to minimize damage from heat waves that stand to expand with the North Pacific high pressure.

The ministry convened an emergency meeting earlier in the day to order relevant ministries and local governments to better protect vulnerable groups, laborers working at construction sites, and to prevent blackouts. 

The "alert" level is issued when daytime highs are forecast to be 33 degrees Celsius or higher throughout 40 percent of the country for three or more consecutive days.

Should heat waves escalate nationwide, the ministry plans to further raise the level to the highest "serious" and assemble the Central Disaster and Safety Countermeasure Headquarters to bolster government-wide responses.