TOKYO -- Officials of Japan's biggest political party yesterday angrily denied reports that the party had received secret cash payments from the CIA a generation ago, but opposition parties said they will not let the issue die.

The New York Times reported Sunday that newly declassified U.S. government documents show a pattern of CIA payments to the Liberal Democratic Party in the 1950s and '60s, when the United States looked on Japan as a bulwark against the spread of communism in Asia.

The Liberal Democratic Party, the most conservative of Japan's major parties, controlled every government of Japan from its founding in 1955 until last summer's "political revolution" ended the era of one-party rule.

After various twists and turns, the party is again part of the ruling coalition. But to regain power, it had to form a marriage-of-convenience coalition with its historical enemy, the Socialist Party.

Opposition parties have been sniping at this unlikely left-right coalition, looking ahead to a national election that could occur as early as next spring.

When the parliament convened yesterday morning, opposition members immediately asked how the Liberal Democrats could take clandestine cash from the U.S. government.

The party's leadership responded by declaring that the New York Times's story was wrong. "We have investigated it, and the story is absolutely not true," said party secretary general Yoshiro Mori.

The report also was damaging to the Socialists. The story said a key reason the CIA wanted to fund the Liberal Democrats was because the Socialists were receiving secret money from the Soviet Union. Prime Minister Tomiichi Murayama, head of the Socialist Party, denied that part of the story

It probably would have been illegal for a Japanese party to receive foreign contributions, but the law is not clear.