South Korea's presidential office said in a statement from Seoul earlier on Wednesday that Saudi Arabia had pledged to "actively consider" supplying additional crude, as Seoul looks for alternatives to Iranian oil.
"Solving the changing policies in the Middle East by peaceful means and as soon as possible will help stabilize global oil prices and limit its impact on the global economy," Lee said in a speech translated into Arabic.
"I believe Saudi can play a major role in stabilizing the global economy," Lee said in the Saudi capital Riyadh after meeting Minister of Petroleum and Mineral Resources Ali Al-Naimi.
Lee is visiting major crude suppliers Saudi Arabia, Qatar and the United Arab Emirates this week to secure stable sources of energy.
Iran is facing toughened US sanctions that make it difficult for buyers to pay for the 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.
South Korea, the world's fifth-largest crude oil importer, sourced some 87 percent of its crude imports from the Middle East last year, with 9 percent coming from Iran.
The United States has pushed Asian countries to cut crude supplies from Iran in a bid to pressure Tehran to rein in its nuclear ambitions, which Washington suspects are aimed at making nuclear weapons, while Iran agues that is for peaceful means.
South Korea owes Iran's central bank some $5 billion for crude oil imports, but the money is trapped in its banking system because of the difficulty of sending money to Iran without falling foul of US sanctions.
