In an effort to head off a potential crisis in student loan availability, the federal government will buy loans from lenders, double the amount of loans it writes directly and bolster a “lender of last resort” program that helps low-income students finance college.

The moves announced Wednesday are aimed at reassuring skittish lenders that they will have ready access to cash throughout the 2008-09 college term, at a time when the credit market is moribund.

“We want students to be able to concentrate on their studies rather than worry about disruptions in the student loan market and whether they will be able to obtain federal loans to help pay for school,” Secretary of Education Margaret Spellings said in a statement.