The cluster emerged in Seoul's Itaewon district.
Two people among the cases first started showing symptoms on May 2, Kwon said, adding that the outbreak may have “various epicenters or sources."
South Korea's handling of the Covid-19 pandemic has been widely praised but the official said recent lapses had caused the latest spike in cases.
“Lowering our guard can call in another infection. That’s the case with the infection in Itaewon clubs," he said.
"The distancing regulation wasn’t carried out properly, the list was not accurate, and therefore, the delay in voluntary report and tracing is very concerning.”
Local media has linked the cases to what it has described as the capital's "gay clubs," raising fears that the LGBT community will be further stigmatized. Government officials have condemned the language used in some press reports.
“Prejudice or discrimination does not help in our epidemic prevention activity. Such prejudice and discrimination in our whole society are actually harmful to epidemic prevention," Kwon said, while speaking to media on Tuesday.