The two men, one aged 20 and the other 26, are suspected ofbetween September and December last year in what police describe as one of the biggest in the country's history.
The two are suspected of obtaining personal and financial data from 12,000 South Koreans who. The pair then sold information on those people to lending services firms in return for 100 million won ($106,400), police said.
Police said they will soon turn over evidence on the pair, who were not named, to prosecutors who will then tell the court what sort of criminal penalties they are seeking against the two.
"This kind of spam mailing is causing enormous problems in South Korea and we think these two are responsible for some of the biggest abuses," a police official said by telephone.