South Korea reported 700 new coronavirus cases, its highest daily figure since early January, and the Prime Minister reiterated warnings on Thursday that new social distancing rules would likely be needed.
Wednesday's tally compares with an average of 477 cases last week, according to data from the Korea Disease Control and Prevention Agency and will fuel fears that the country may be facing a fourth wave of infections.
Prime Minister Chung Sye-kyun told a government meeting a new wave of infections could disrupt South Korea's vaccination programme which has been suffering delays as the international vaccine-sharing scheme COVAX struggles to provide promised doses on time.
South Korea also said on Wednesday it will temporarily suspend providing AstraZeneca's Covid-19 vaccine to people below 60 as it undergoes reviews in Europe.
It also approved a Johnson & Johnson shot in a bid to speed up its inoculation rollout.
Officials have said that a new round of restrictions are likely to be announced as soon as Friday. South Korea currently limits private gatherings of more than four people.
South Korea has to date reported 107,598 infections in total, with 1,758 deaths.