Legislation that aims to ensure that student loans remain available despite the ongoing credit crunch was passed by the Senate Wednesday, but only after changes that will require further action by the House.

The White House, lawmakers from both parties and the higher education community are eager to see Congress clear the bill, which would increase the amount of money students can borrow through federally backed loans and increase the Education Department’s role in ensuring their availability.

Education Department officials have said that in order to help, the bill needs to be on the president’s desk before the heaviest demand for student loans begins this summer.

The president — and some Republican senators — wanted the Senate to clear the version of the bill passed by the House on April 17. But Sen. Edward M. Kennedy , D-Mass., chairman of the Health, Education, Labor and Pensions Committee, refused to accept the House approach, choosing instead to amend the measure and return it to the House.

“I’m grateful that the Senate has acted so quickly to pass this needed legislation,” Kennedy said in a statement. “Millions of families are facing difficult economic challenges at every turn, with this legislation, their children’s college dreams won’t become the next victims of today’s troubled economy.”

The bill would increase the total amount of federally backed loans that students can borrow and would allow the Education Department to buy existing loans in order to give lenders the money they need to make new ones.

The credit crunch has driven more than 50 lenders out of the federally backed student loan program. Bill sponsors say that allowing the Education Department to purchase existing loans would keep more lenders in the business until market conditions improve.