DES MOINES, JAN. 9 -- Senate Minority Leader Robert J. Dole (R-Kan.) demanded today that Vice President Bush release all documents and evidence about his role in the Iran-contra affair, but Bush responded that Dole should "do a little homework" and read material already delivered to Congress.

Bush in turn demanded that Dole and others release financial disclosure reports and tax returns. Dole replied, "he's just trying to change the issue."

The two leading Republican presidential contenders devoted another day to exchanging sharp retorts over the Iran-contra affair following Bush's charge at the Des Moines Register debate Friday night that he had been unfairly criticized in the newspaper for failing to answer questions about his role in the scandal.

The vice president's aggressive stance at the debate -- aiming his fire at moderator James P. Gannon, editor of The Register -- appeared to preempt criticism from most of the other Republican aspirants, but Dole returned immediately to the issue this morning in remarks to reporters.

"It may be sort of the ghost of Spiro Agnew coming into Iowa and taking on the press," Dole said, referring to the then-vice president who criticized news media coverage in President Richard M. Nixon's 1972 reelection campaign.

Dole also said Bush should make public "all data, all conversations" he had during the Iran-contra affair, except for his advice to President Reagan, which Bush has refused to disclose. "Why doesn't he release what we're all trying to find out about, the Iran-contra thing?" Dole asked. Bush made documents available to Congress, but the report of the Iran-contra investigating committees said little evidence was found of his role in the affair.

Later today, Bush repeated the approach he started on Thursday of pausing in front of reporters and volunteering to take any questions on the spot about his role in the Iran-contra affair. He said "I'd be glad to" release the documents Dole asked about but "I think some of that is classified."

"Why didn't he ask that last night?" Bush asked, referring to Dole. The vice president said the Senate investigated the Iran-contra scandal and "he {Dole} has access to everything that's been provided in the Senate. I suggest he do a little homework."

"I suggest he take a little time off from the campaign and read 'em," Bush said. "And if he has any specific questions, ask them."

"This is the new me," Bush said. "I don't want to get into a big discussion with Bob Dole. They all had an opportunity last night, and I didn't hear any of this. It's always around behind, after I've left that we get all this."

When a reporter questioned Bush about the comparison with Agnew, the vice president did not answer. "Next question," he said tersely.

Bush was asked to explain how he could not have known about the arms-for-hostages deals with Iran, as he has claimed he did not, given his statements that he was a full participant in the Reagan presidency.

The Washington Post reported this week that Bush attended dozens of meetings at which the Iran arms sales were discussed, but Bush wrote in his autobiography that he did not learn the full story of the arms-for-hostages trade until December 1986, more than a year after the arms sales began.

"Well, the president didn't learn the whole story either," Bush said today. "These weren't national security meetings. And even if they were, you wouldn't have learned the full story. So the same reason the president didn't learn is why I didn't learn, until the hearings were all over."

Bush acknowledged that in retrospect the arms sales "subverted" a policy that he had publicly advocated of not making concessions to terrorists, but he said "we did not perceive it to be arms for hostgages" at the time.

Asked about a computer message showing that he sought to delay a 1986 trip to Tehran by former national security adviser Robert C. McFarlane until after Bush returned from his own trip to the Persian Gulf region, Bush said he knew of the McFarlane mission to Iran. Questioned whether he knew of the arms-for-hostage deals then, Bush said, "The same answer the president has given is the answer I give you." But he did not elaborate.

Bush lieutenants tried repeatedly today to raise questions about Dole's wealth. Bush called at the debate for all the Republican candidates to release their tax returns and make full financial disclosure. Bush's campaign communications director, Peter Teeley, told reporters that records would show Dole was paid more than $500,000 last year. Teeley said he was mentioning it to show that the senator and his wife, Elizabeth Hanford Dole, are not in the same economic class as Iowa farmers.

The Iran-contra affair has dominated the vice president's campaign activities all week and continued to do so today after he left Des Moines for a campaign stop in Madison, Wis. Protesters greeted Bush with placards saying "Bush Pinochio in '88" and "Bushgate."

After a brief campaign speech, Bush again invited questions from reporters and was asked about a note he wrote in 1985 praising former National Security Council aide Oliver L. North for his work on Central America and the American hostages.

Bush praised Marine Lt. Col. North today for his combat record in Vietnam while others were "tearing up the American flag." He said North "risked his life" by accompanying McFarlane to Tehran. Bush denied that North's private network of aid for the contras fighting the government of Nicaragua violated the Boland Amendment against such aid.