The Obama administration on Wednesday sought to bolster support for its plan to overhaul student lending, attacking banks that oppose it for enjoying “a free ride from taxpayers for too long.”

In a telephone conference with reporters, Secretary of Education Arne Duncan repeated the administration’s assertion that the direct offering of student loans by the federal government, and an end to subsidies to private lenders, would save taxpayers $87 billion over 10 years. The savings would be used to aid early-childhood education, community colleges and needy college students.

The administration plan passed the House of Representatives last year but has stalled in the Senate. Mr. Duncan said he remained confident that the Senate would pass the measure, which President Obama has called a “no-brainer.”

But the banks that have offered the most loans, with federal subsidies and guarantees, have hired lobbyists and mounted advertising campaigns, saying the plan would cost jobs and reduce consumer choice. Congressional aides say passage is in peril.