U.S. authorities have repeatedly warned that foreign Internet hackers are probing U.S. critical infrastructure networks, including those that control utility plants, transportation systems and financial networks.

‘‘We know of specific instances where intruders have successfully gained access to these control systems,’’ Panetta told the business group. ‘‘We also know that they are seeking to create advanced tools to attack these systems and cause panic and destruction, and even the loss of life.’’

Business leaders, including the U.S. Chamber of Commerce, were opposed to the legislations, arguing it would expand the federal government’s regulatory authority companies already struggling in the tough economy. The bill also encourages more information sharing between the government and private companies.

Panetta pressed the group to support the stronger cybersecurity measures, warning that failure to do so could have catastrophic consequences.