After declining for three years, illegal immigration across the southwestern border is again on the increase, thanks largely to fake Social Security cards, according to officials.

"The word is going back that if you can obtain, at a minimum cost, a driver's license and fraudulent Social Security card, that's all you need to meet the burden of proof to work in the United States," said Duke Austin, a spokesman for the Immigration and Naturalization Service.According to INS figures, apprehensions of people trying to cross the southern border illegally rose from 854,128 in the fiscal year that ended Sept. 30, 1989, to more than 1 million for the fiscal year that ended last Sept. 30.