Kim Myung Kyu was taken into custody for questioning on May 17 in relation to the charges which allege he accepted bribes worth 110 million won ($124,885) from a gas transport company in return for awarding a contract.
The arrest took place just after Kim returned from Moscow, where Kogas and Gazprom signed a memorandum of understanding covering a range of fields for future cooperation.
At a news conference with his counterpart Alexei Miller, the Moscow Times reported that Kim gave no indication that he was in legal trouble, jovially telling Miller that working together would be natural since they both ran state-owned companies.
The North West Shelf, which recently won a seven year LNG supply contract with Kogas, said all its dealings with the company had been professional and entirely proper.