South Korea's environment and forest authorities said they will implement a joint search operation to find dead wild boars near the border, as they could be infected with the virus.
About 440 officials will carry out daily patrols in the designated areas.
South Korea will also induce wild boars to move to northern regions and allow the use of guns in a wider area.
The number of dead wild boars that have tested positive for the disease has risen to 15, although no additional cases of ASF have been confirmed at local pig farms since early this month, with the figure staying at 14.
In May, North Korea reported its first outbreak of the disease at a farm near its border with China to the World Organization for Animal Health. The animal disease appeared in South Korea in mid-September, but it remains unknown how the virus traveled into South Korea.
On Sunday, South Korea said it will build fences stretching from the western border city of Paju to Goseong in the east coast.
"The decision came amid rising concern that wild boars may travel longer distances during the breeding season," Vice Agricultural Minister Lee Jae-ouk said a meeting at Sejong Government Complex in central South Korea.
The disease is not harmful to people, but it is fatal for pigs and there is no cure currently available.
South Korea, Asia's fourth-biggest pork consumer, has slaughtered and buried more than 154,000 pigs since the outbreak started. (Yonhap)