South Korea reported 382 new COVID-19 cases on Wednesday.
Of them, 363 were locally transmitted,the largest number of local transmissions since the nation's peak in late August.
The increasing number of cases can be attributed to more cluster infections.
A mass infection was reported on Wednesday at a military unit in Yeon-cheon County in Gyeonggi-do Province.
A total of at least 60 soldiers have tested positive, and with around one-thousand military personnel undergoing testing, more are expected.
A cluster infection was also seen in the city of Jinju, located in Gyeonsangnam-do Province, with 19 people testing positive, mostly city officials who went on a business trip and their family members.
To prevent further spread of the virus, the Central Disaster Management Headquarters has revised the social distancing guidelines.
Rule number one requires people to "wear masks indoors and in places outside where social distancing is not possible', highlighting the importance of wearing masks.
The original number-one rule was to stay home for three to four days if showing symptoms.
"We expect a bit more time to be needed for the social distancing measures to show their effectiveness, so up until next week will be a critical period for us in stopping the virus."
Prime Minister Chung Sye-kyun has called for cooperation from local communities with concerns rising ahead of next week's college entrance exam.
"I ask for local communities and schools for their cooperation to ensure that students taking the upcoming college entrance exam are not being exposed to COVID-19."
As more than 70-percent of domestic infections came from Seoul and its surrounding areas, the government imposed Level Two social distancing measures starting Tuesday.
The heightened measures are likely to remain in place for two weeks.
Bae Eun-ji, Arirang News.