Individuals who entered or lived in North Korea at any time since March 2011 will not be allowed into the United States under the Electronic System for Travel Authorization.
The U.S. Department of Homeland Security announced the new measures on Monday.
ESTA allows people from 38 countries including South Korea to visit the U.S. for up to 90 days without a visa.
But under the new measures, apart from a few exemptions for diplomatic and military purposes, anyone who has been to North Korea since 2011 will need to apply for an appropriate visa at the U.S. embassy.
The U.S. applies similar restrictions to people who have visited certain other countries including Iraq, Iran and Syria.
