The House Government Operations Committee, in a sharply divided report, accused the Justice Department yesterday of a "massive, baffling and unconscionable" delay in failing to sue distributors of three-wheel all-terrain vehicles (ATVs), which a safety agency has described as extremely hazardous.

The report offered rare Democratic praise for the Consumer Product Safety Commission, hailing its declaration Dec. 12 that the vehicles pose "an imminent and unreasonable risk of death, serious injury or severe personal injury."

The committee's 26 Democratic members said they could not understand why the Justice Department has not acted on the CPSC's February request that it sue distributors of the machines to force dealer refunds for those sold to youngsters under 16.

The department has "acted irresponsibly" by failing to inform the commission of its plans, the committee said.

A Justice Department official declined to comment on the report.

The report drew sharp dissent from the committee's 12 Republicans, who said the CPSC has "more worthwhile and productive" issues than ATVs and predicted that the department would lose a lawsuit about the vehicles.

Sounding a note similar to defenses raised by ATV distributors, the Republicans said more than half the 789 deaths attributed to ATV accidents were the result of operator error.

The Republicans, led by Rep. Larry E. Craig (Idaho), also said that "the numbers are simply not there" to support a recall or other actions recommended by the CPSC. The GOP minority disputed claims, widely voiced by safety groups, that ATVs lead to 20 deaths and 7,000 hospitalizations monthly.

An estimated 2.1 million ATVs are in the United States, and the committee majority said sales by the four dominant manufacturers -- Honda, Yamaha, Kawaski and Suzuki -- have increased dramatically in recent years.

Use of the vehicles long has been a subject of congressional complaints. In July 1986, the House panel urged the CPSC to move against the vehicles, citing high accident rates.

"Presumably, the Justice Department is preparing a lawsuit, but committee's report finds the delay to be an untenable situation," said Rep. Doug Barnard Jr. (D-Ga.), chairman of the commerce, consumer and monetary affairs subcommittee.

"First, such a delay of over nine months since the commission voted makes a mockery of the concept of 'imminent hazard,' " he said in a statement. "Second, the Justice Department should have immediately informed the CPSC that it would take this so, so that the CPSC could have chosen alternative options."