Energy Secretary John S. Herrington lashed out yesterday at Japan for its refusal to support the U.S. oil embargo of Iran, saying the Japanese position is "totally unacceptable" and the country's leaders had "better rethink their position."

"I am deeply disappointed at the Japanese response to our request to help us in what is a difficult situation of enforcing an oil embargo," Herrington said in an interview. "There is a chance to do something for a friend at a time when Japan needs to do something for a friend."

Herrington was reacting to reports that Japan on Saturday informed Undersecretary of State Michael H. Armacost, who was then visiting Tokyo, that it will not support the recently announced U.S. trade embargo against Iran.

Japanese officials sought to assure Armacost, however, that they will try to avoid undercutting the U.S. embargo by not increasing their purchases of Iranian oil.

"That's unacceptable, that is totally unacceptable," Herrington said of the Japanese response. He called the reply "preliminary," adding "I think {the Japanese} had better rethink their position."

He said he was expressing his personal views as secretary of energy but added that "it's a view that is shared by a number of high officials in the administration, I guarantee you that."

Herrington said Japan could have easily bought its oil from the Arab producers in the Persian Gulf instead of from Iran. Japan purchases about 20 percent of Iran's total oil exports, which average between 1.5 million and two million barrels a day.

The secretary said U.S. officials were particularly upset by the Japanese attitude because they feared it would serve as "a big signal" to other Western European nations like Italy and West Germany, who have yet to take a position on the U.S. trade embargo of Iran.

Only France has imposed a trade embargo on Iran.

If Japan had supported the embargo, Herrington said, then Italy would have been more likely to have joined it, too. Italy, he said, now refines most of Iran's oil.

"We have to have support or it's not going to be successful," Herrington said of the U.S. embargo, which he acknowledged would be extremely difficult to enforce in any case.

The secretary defended the administration's decision to impose an embargo, saying it was "a moral issue" and "a moral stand," taken after discovering Iranian oil exports to the United States had soared in July.

He said there were only two ways to pressure Iran into ending its war with Iraq -- a cutoff of all arms sales or financial pressure applied through an oil embargo.