The Nicaraguan rebels' chief spokesman dismissed reports of a mutiny in the ranks and said the leadership was seeking proof of allegations of corruption against their top military leader.

Bosco Matamoros said Thursday night that dissidents demanding the removal of military commander Enrique Bermudez are fewer than the 726 rebel fighters at a base camp near the Nicaraguan border.He would not give a more specific estimate. There have been reports 2,000 rebels were engaged in a mutiny at the camp in Yamales, a Honduran town 20 miles north of the Nicaraguan border.

"There is not a climate of confrontation there," Matamoros said in an interview. "They have a legitimate right to differences of opinions.

"But from that, to conclude that the organization is at a breaking point . . . would be to ignore the fact that this organization has 17,000 men."

Independent estimates have put rebel strength at half that number.

Bermudez and two civilian leaders of the Contras, as the U.S.-supported rebels are known, met in Yamales this week with some of the combatants who have accused him of corruption and inefficiency.

Honduran authorities barred journalists from traveling to the camp.

Matamoros, who said he also visited the camp, disputed claims by some Contra sources that 4,000 rebels troops were there.

"That's one of the most fantastic things I've heard," he said, contending that 4,000 combatants were strung along the entire Honduran-Nicaraguan border.

The dissent attracted attention last week when Honduras deported seven Contra field commanders to the United States.

Matamoros said the seven had publicly discussed rebel issues, a sensitive point for Honduras, which for years has barely acknowledged the existence since 1981 of Contra base camps on its soil.

A dissident field commander who was not deported, Diogenes Hernandez Membreno, fled to Yamales.

Matamoros said he was briefly detained along the road to the camp Sunday by some of Hernandez Membreno's men, who he said number about 200.

The spokesman said grumblings about Bermudez surfaced last month, and the Contras' military directors sent a letter April 20 requesting a meeting to discuss the allegations.

Matamoros said that three dissident field commanders including Hernandez Membreno had responded in an April 26 letter but had not produced material proof of their accusations that Bermudez was corrupt and inefficient.

He said the Contras' 27-member council of regional commanders would investigate the charges and decide whether disciplinary action is warranted. Bermudez could only be removed by the Contras' civilian leadership.

Matamoros dismissed claims Bermudez opposes forging a lasting peace with Nicaragua's leftist Sandinista government.

He said Bermudez, while at Yamales on Wednesday, told the troops he "fully endorsed the process of negotiations" with the Sandinistas to try to end the 61/2-year-old war.

Bermudez, 46, was Nicaragua's representative to the Inter-American Defense Board in Washington D.C., under President Anastasio Somoza, the rightist dictator overthrown by the Sandinistas in 1979.

On March 23, Sandinista and Contra leaders signed a preliminary peace accord. A 60-day truce took effect April 1, during which the two sides were supposed to negotiate conditions for a permanent peace that would give the Contras a role in the political process.

Two rounds of high-level negotiations in Managua since have failed to produce substantial progress. Foremost among issues dividing the two sides are how to guarantee security for the Contras once they move into designated cease-fire zones in Nicaragua.

The date for the next round of talks has not been set.