The expanding insider stock trading scandal forced former Prime Minister Yasuhiro Nakasone to delay his scheduled trip Wednesday to the United States and stalled debate in parliament on a supplementary budget.

Opposition parties refused to discuss the $41 billion budget, demanding instead that Nakasone testify on his links to Recruit Co., a major job placement publishing company at the center of the scandal.Nakasone, who was prime minister for five years until October 1987, told reporters he postponed his U.S. trip scheduled to start Wednesday. He was to meet President Bush and former President Ronald Reagan during the two-week tour.

He said he delayed the trip until after the supplementary budget is passed, and "I will then consider whether to go ahead with the journey."

Nakasone, in a nationally televised news conference Monday, denied involvement in the scandal and said "I do not recognize the necessity of my being summoned to the Diet (the Japanese parliament) because I am totally innocent."

News reports said two of Nakasone's aides received 29,000 shares of Recruit Cosmos Co., a real estate subsidiary of Recruit Co., in 1986 prior to their being listed publicly. This allowed the aides to make huge profits.

Nakasone said he was briefed on the stock purchases a month after he stepped down as prime minister, but he said the transactions were "for social purposes" and not influence-buying.