South Korea's presidential office said in a statement on Wednesday that Saudi Arabia would "actively consider" support including additional crude supplies if requested by Seoul, as it looks for alternatives to Iranian oil.

The remarks came in a meeting between Saudi Arabia Oil Minister Ali Al-Naimi and South Korean President Lee Myung-bak.

"President Lee requested stable crude supply to South Korea in the event of an emergency, and Minister Naimi responded that Saudi Arabia would actively consider support including additional supply if South Korea requests," the statement said.

Lee is visiting major crude suppliers Saudi Arabia, Qatar and the United Arab Emirates this week to secure stable sources of energy.

South Korea, the world's fifth-largest crude oil importer, sourced some 87 per cent of its crude imports from the Middle East last year, with 9 per cent coming from Iran. It imported 2.54 million barrels per day (bpd) of crude last year, with its top five suppliers Saudi Arabia, Kuwait, Qatar, the United Arab Emirates and Iran.

Iran is facing toughened U.S. sanctions that make it difficult for buyers to pay for its crude. Countries that reduce imports can secure a waiver, but South Korea last year increased Iranian imports by a fifth, and has set annual deals for slightly more this year.

Iranian money, an estimated $5 billion so far, is piling up in South Korean banks as South Korean refiners continue to pay for shipments in won, which the banks cannot legally transfer back to Tehran.

On Sunday, U.S. President Barack Obama authorized new measures which extend sanctions to all Iranian financial institutions and require financial institutions doing business in the United States to block and freeze transactions having a suspected link to Iran.