A new law authorizing reparations for Japanese-Americans interned during World War II helps lift "an unjust burden of shame" borne by 120,000 loyal citizens for four decades, says a congressman who was among those incarcerated.

"Today is a moment of great emotion for me, a day when hopes and dreams have become reality," said Rep. Norman Mineta, D-Calif., as President Reagan signed the bill Wednesday.The bill authorizes tax-free payments of $20,000 to each of the approximately 60,000 surviving veterans of wartime camps, many of whom spent three years in internment.

The Japanese-Americans were rounded up and sent to the camps under an order issued by President Franklin D. Roosevelt after the Japanese attack on Pearl Harbor, Hawaii, on Dec. 7, 1941, plunged the United States into World War II. Many Japanese-Americans lobbied for the legislation for years. It finally cleared Congress by a 257-156 vote in the House on Aug. 4.

Reagan originally objected to some features of the bill, saying it would be too costly, but he backed the final version, which calls for a fund of $1.2 billion, with appropriations in any one year limited to $500 million. Legislation providing the actual money must still be enacted.

In signing the bill, Reagan said, "What is most important in this bill has less to do with property than with honor. For here we admit a wrong. Here we reaffirm our commitment as a nation to equal justice under the law."

Mineta, who as a child of 10 was taken to an internment camp in Wyoming, said, "Today the unjust burden of shame which 120,000 loyal Americans have carried for 46 painful years has at long last been lifted."

Many of the 250 Japanese-Americans who attended the signing ceremony said it is the principle of the bill, not the money, that matters.

Among them were six members of one family - now scattered in California, Georgia and Oregon - who were taken from a farm near Stockton, Calif., to an internment camp at Rohr, Ark.

Dr. Walter Emori, now 47 and an arthritis specialist in Medford, Ore., was 3 when the family was interned.

"We see this as a healing process which says the country recognizes that a wrong was being done and in one small way perhaps is trying to make amends for this," Emori said.

"In general, the Japanese-American people who went to camp recognize that it was an awful, hysterical, grim time in American history, and although we all feel badly that we had to go and that we were rounded up and not only had our personal belongings but our civil liberties taken away from us, it's kind of understandable as to why this should happen," he said.

Emori noted that his family has prospered since the war, as have many other Japanese-Americans.

"We as a family would like to take this gesture the next step further and say we'd like to give this back to the country for the good that came out of the awful," he said.

He said the family plans to use its total payments of $120,000 for such a gesture, possibly to an endowed professorship at Loma Linda University in California.