Most of the Indian companies that sponsor large numbers of U.S. visas are "publicly listed and ethically managed," the National Association of Software and Service Companies (NASSCOM) said today. However, India's chief outsourcing association has admitted there may be instances of U.S. visa abuse by Indian companies.

NASSCOM said the problems are confined to "small, fly-by-night operators," admitting that small companies are "an area that may need more attention."

The association's comments come after further allegations of U.S. visa abuse by two U.S. senators this week. Following their complaints last month about alleged misuse of H-1B visas by Indian outsourcers, U.S. Senators Chuck Grassley (R-Iowa) and Dick Durbin (D-Ill.) this week questioned the use of large numbers of L visas by Indian outsourcers.

Information from the U.S. Bureau of Citizenship and Immigration Services (BCIS) indicated that the companies using the most H-1B visas are the same firms that use the most L visas, the senators said. That made them suspect that companies are using L visas to circumvent worker protections required under the H-1B program.

The allegations come as the U.S. Senate attempts to revive an immigration reform bill that includes a provision for increasing the number of H-1B visas available.

Earlier this month, Patni Computer Systems Ltd. reached an agreement with the U.S. Department of Labor to pay back-wages to employees brought to the United States under the H-1B visa program, who then worked at lower salaries than U.S. workers would get for similar work. Patni is among the top 10 users of H-1B and L-1 visas from India.

The senators wrote letters to nine Indian companies in May, asking them for details on their use of H-1B visas. Among the companies were top Indian outsourcers including Tata Consultancy Services, Infosys Technologies and Wipro. The nine companies together account for close to 20,000 visas, the senators said.

Companies appear to be increasingly using H-1B visas to displace qualified American workers, Grassley said in May. India's Minister for Commerce and Industry Kamal Nath warned at the time that the complaints could have repercussions at the ongoing World Trade Organization (WTO) negotiations, since the issue of work permits is a trade issue. Those negotiations fell through this month, not due to work permits but on account of differences over subsidies and tariffs on agriculture products.

NASSCOM replied to the two senators in May but has yet to receive any acknowledgement, the association said on Thursday. It said it looks forward to a positive engagement that will address the politicians' concerns without disrupting the growing two-way trade between India and the United States.