Two of the largest U.S. business-lobbying groups criticized a Senate cybersecurity bill aimed at shielding vital computer networks, saying the measure would burden companies with unneeded and costly regulation.

The bipartisan legislation introduced yesterday calls for the U.S. Homeland Security Department to identify systems critical to national and economic security and set security rules for overseeing companies and government agencies.

Lawmakers and regulators say rules are needed to fight increasingly sophisticated cyber attacks capable of disrupting power grids, banks and communications networks. Industry groups said the bill's broad approach may raise costs for businesses and be too prescriptive, particularly for financial companies held to high security standards by regulators.