Financial authorities have found 22 cases of alleged hiring irregularities at Shinhan Financial Group between 2013 and 2017.

The Financial Supervisory Service's(FSS) month-long investigation found Shinhan Bank hired 12 entry-level workers in 2013 who were disqualified during the hiring process.

Of the 12 workers, five were children of the bank's executives at that time and the remaining seven were children of influential officials.

Ten other hiring irregularities were found at Shinhan Financial's credit card and insurance units. 

The FSS referred the cases to prosecutors for further investigation and the country's four major lenders, Shinhan, KB Kookmin, Woori and KEB Hana are now subject to the prosecution's investigation.

Since last year, the banks have come under fire for allegations that they gave undue favors or special treatment to job applicants with ties to top bank executives or top-tier customers.