The Reagan administration's chief defender of aid to Nicaraguan rebels and House Democrats' chief critics of that policy renewed their disagreements at top volume yesterday as the House began preparing for another vote on the issue.

The White House also charged that Nicaragua "dug in its heels" at the guidance of Cuban advisers to derail the Contadora regional peace talks last weekend.

Elliott Abrams, assistant secretary of state for inter-American affairs, defended the controversial U.S. account of the early hours of the incursion by Nicaraguan troops into Honduras March 22. He said the leftist Sandinista government of Nicaragua "simply lied about what it had done," while U.S. accounts that 2,400 soldiers had invaded were accurate.

"We have been proven correct -- perhaps even to have underplayed the event -- by further intelligence, by prisoner debriefings and even by [Nicaraguan President] Daniel Ortega," Abrams told the House Foreign Affairs subcommittee on Western Hemisphere affairs.

"Are you telling this committee you didn't hype this?" Rep. Peter H. Kostmayer (D-Pa.) asked later.

"I played it down, sir," Abrams responded.

"Good Lord, I wouldn't want to be around when you played it up!" Kostmayer exclaimed. He noted that the official estimate of the number of Sandinista troops went from 2,400 in private briefings for members of Congress to 1,500 in public statements, while other estimates were even lower.

"Most people feel you did hype it . . . people are feeling you've been untruthful on this issue," Kostmayer said.

Abrams bristled at "this personal attack" and advised Kostmayer that "it would be a damn good idea" for doubtful members of Congress to examine classified State Department cables on the matter.

Asked about conflicting early accounts of whether Honduras requested the $20 million in military aid that President Reagan immediately provided, Abrams said he and Honduran President Jose Azcona Hoyo might have "short-circuited the usual diplomatic system" in their private consultations and caused "a time lag in getting the story out in Honduras."

He said Azcona called Washington the morning of March 24 to request aid, and Abrams called back twice that afternoon to discuss it. But those calls were private, Abrams said, and meanwhile a Honduran government spokesman denied publicly that aid had been requested and "never caught up."

Earlier, subcommittee Chairman Michael D. Barnes (D-Md.) said his visit with Reps. James C. Slattery (D-Kan.) and William B. Richardson (D-N.M.) to the Contadora negotiating session in Panama last weekend convinced them that leaders of the eight Latin American nations are "clear, strong and unambiguous" in opposition to any U.S. humanitarian or military aid for the Nicaraguan rebels, known as contras or counterrevolutionaries.

"Their language was not even diplomatic," Barnes said. However, the eight also agreed "that Nicaragua is being intransigent, that the Sandinistas' commitment to peace is suspect," he said.

Nicaragua rejected a proposal that would have reduced arms levels in all of Central America, arguing that contra attacks would have to stop first.

At the White House, spokesman Larry Speakes said the Sandinistas "consistently had Cuban advisers playing a substantive role" in setting Nicaragua's positions at the talks. "Nicaragua has refused to take part in constructive talks . . . we are willing, but the Sandinista government has dug in its heels."

Renewed House action on Reagan's once-rejected request for $100 million in contra aid begins Thursday when the Rules Committee is scheduled to decide which of several alternatives will be allowed to reach the floor as amendments to a $1.7 billion supplemental appropriations measure.