A senior official of Japan 's largest refiner by capacity said Tuesday only Saudi Arabia can make up for a supply gap if a large part of the global community stops buying Iranian crude oil.

"Think about 2 million barrels a day of output from
Iran . There is virtually only Saudi Arabia you can look to," said Tsutomu Sugimori, JX Nippon Oil & Energy Corp.'s Senior Vice President.

The oil refining unit of JX Holdings Inc. (5020.TO) is one of
Japan 's two largest users of Iranian crude oil. The other is Showa Shell Sekiyu KK (5002.TO).

The U.S. Congress approved last week legislation that would embargo foreign institutions from businesses with U.S. banks if they have dealings with the Iranian central bank, which is the main institution handling transactions related to crude oil exports from the Middle Eastern country.

Sugimori said JX hasn't started preparing for a possible ban on Iranian crude imports, as U.S. President Barack Obama hasn't yet signed the bill.

Showa Shell President Jun Arai said earlier this month that the company wasn't going to halt Iranian crude oil imports for the time being, but it wouldn't be difficult to find new supplies even if the possible ban takes place. Showa Shell is an affiliate of Royal Dutch Shell Plc (RDSA) and state-owned Saudi Arabian Oil Co.

Iran accounts for roughly 10% of Japan's crude oil imports.