A three-judge federal panel yesterday dismissed a 1980 census challenge contending that illegal aliens should be counted separately and excluded from the population base used to apportion congressional representatives to the states.

A group of immigration reformers and members of Congress had contended in U.S. District Court that including aliens in the census would result in unfair designation of legislators and federal funds to states with the largest population of illegal aliens.

The group, led by the Federation for American Immigration Reform, said the historical intent of the Constitution was that only lawful U.S. citizens to counted. The government, which has devised various ways to seek out the so-called "hidden" illegal alien population, argued that the Constitution mandates that "the whole number of persons" in the United States be counted.

However, the special three-judge court said the immigration reformers had failed to show they had incurred any harm from inclusion of illegal aliens in the count, nor had they shown they would benefit from a separate count.

Therefore, the court said, the group did not have sufficient grounds to bring their claim.

U,S. Appeals Court Judge Patricia M. Wald and U.S. District Court Judges Oliver Gasch and Barrington D. Parker participated in the decision.

The court, in a 24-page opinion, added that the government had made "a convincing showing" that any attempt at a separate count of illegal aleins "would be extremely expensive, delay the census by as much as a year and likely be ineffective."