UPDATE 1-Hyundai firms win case to buy refiner stake from IPIC

* ICC directs IPIC to sell $2.25 bln stake in Hyundai Oilbank

* Hyundai Heavy and other affiliates to buy 70 pct stake

* Mediation sought due to dispute over option exercise (Adds details, shares)

SEOUL, Nov 16 (Reuters) - The International Chamber of Commerce (ICC) has ruled in favour of Hyundai companies seeking to buy a stake in an affiliated refiner, worth about 2.6 trillion won ($2.25 billion), from International Petroleum Investment Co (IPIC), a Hyundai firm said.

Hyundai Heavy Industries (009540.KS) said on Monday the ruling would see Abu Dhabi-based IPIC sell its entire 70 percent stake in Hyundai Oilbank at 15,000 won apiece to Hyundai shareholders.

Shareholders related to the former Hyundai Group own a combined 30 percent stake in Hyundai Oilbank, including 19.87 percent held by Hyundai Heavy and 4.35 percent owned by Hyundai Motor (005380.KS).

IPIC, which invests in oil-related projects for the government of Abu Dhabi, acquired 50 percent of Hyundai Oilbank in 1999 and took another 20 percent in 2003.

A dispute began in early 2008 when Hyundai Heavy announced it would exercise an option to buy IPIC's stake, saying IPIC tried to sell part of its stake in violation of an earlier agreement.

Hyundai Heavy had requested the judgement of an arbitration body under the Singapore ICC.