Two members of Korean religious sect Shincheonji - which is at the heart of the outbreak in South Korea - had visited the virus epicentre of Wuhan, says the Korean Centre for Disease Control and Prevention.
One of them came down with the coronavirus as a result. It is not clear when the visit took place.
More than half of all infections in South Korea involve members of the fringe Christian group.
All 230,000 members of the church have been interviewed. Nearly 9,000 said they were showing symptoms.
The sect's leader, Lee Man-hee, has apologised for the outbreak - saying it was "not intentional".