Financial authorities are expanding their inspection of internal control systems at local brokerage firms in the wake of a recent error at Samsung Securities. 

The Financial Supervisory Service(FSS) said on Wednesday that it will carry out a joint on-site inspection of 32 brokerages and KOSCOM, a securities computerization agency in cooperation with the Korea Exchange and the Korea Securities Depository from Wednesday to June first.

FSS officials plan to look into the firms' internal control systems, stock trading procedures and guidelines in cases of errors.  

The FSS recently completed its inspection into six brokerages, including Samsung Securities.

Last month, Samsung Securities mistakenly issued about 100 billion U.S. dollars worth of its own "ghost" stocks and paid them to its employees as dividends.

Although the stocks were never issued and did not exist on the market, 16 employees were able to sell about five million shares.