The expected level of debt to be written off had been set at 28% in 2010, which had risen to 35% by 2013.
Labour's university spokesman, Liam Byrne, said figures from the House of Commons library showed this had risen to more than 40%, which would cost a further £600m.
"We may be at the point where so many students loans are being written off, that the government's new student finance system is actually more expensive than the old arrangements, even though the government is asking students for three times as much money," said Mr Byrne.
I wonder if anyone is actively doing that analysis?
Student loan repayment needs tighter controls, say MPs
I wonder if anyone is actively doing that analysis?