The raid that took place Friday concerns a possible kickbacks paid by a contractor who is also under suspicion of bribing Korean officials by hiring prostitutes and hosting parties at his home at which prostitutes were made available for various officials.
Yonhap News reported the contractor, whose surname is Yoon, is also suspected of drugging women at his house to have sex with them.
Raiding the Daewoo headquarters was not connected to the sex scandal, authorities said.
A National Police Agency officer said the raid was a follow up on "circumstantial evidence of an alleged bribery exchange between Yoon and Daewoo Construction."
Daewoo is suspected of accepting kickbacks from Yoon in return for a contract for building a golf course in Chuncheon Gangwon Province in northeastern South Korea.