Two of the congressmen who last week disclosed the Justice Department's plan to settle a long-pending dispute over the safety of all-terrain vehicles yesterday appealed to the department to delay filing a consent decree over the issue.

Reps. Doug Barnard Jr. (D-Ga.) and James J. Florio (D-N.J.), chairmen of committees that deal with consumer issues, said they want the delay because the proposed settlement is "woefully deficient" and "does nothing to encourage the return of these dangerous vehicles." The department has notified the all-terrain vehicle manufacturers and importers that it is planning to sue them on Dec. 30 unless they agree to the proposed decree by Thursday.

In a letter to Assistant Attorney General Richard K. Willard, the two lawmakers renewed their complaint that the Justice Department proposal drops a refund provision suggested by the Consumer Product Safety Commission.

The safety commission, which labeled all-terrain vehicles an "imminent hazard," referred the issue to the department a year ago, urging that it sue importers and seek, among other things, to force voluntary refunds to owners of three-wheeled models and to owners of any models sold to children under 16.

All-terrain vehicles (ATVs), made mostly in Japan, are motorized, off-the-road vehicles that have been linked by the safety commission to a high rate of serious injuries, especially among young drivers, who are not required to have a driver's license to operate them. More than 2 million ATVs have been imported into the United States, most since 1979.

The two congressmen said yesterday that they want the delay to allow the public time to comment on the proposed settlement and to give them time to file legal briefs seeking to intervene in the proposed lawsuit that would accompany the filing of a consent decree.

Justice Department officials had no comment on the letter to Willard.