Almost half of England's further education colleges have seen a decline in student numbers - with the drop blamed on the scrapping of the Education Maintenance Allowance (EMA).
An Association of Colleges survey shows 49% have fewer students than last year.
Financial pressures, such as the loss of the EMA allowance and the cost of transport, are named as the reason.
The Department for Education said financial support was now targeted at students "who need it most".
Fiona McMillan, president of the Association of Colleges and principal of Bridgwater College, says that it is particularly the poorest students, with the lowest skill levels, who are not enrolling.
Cost of transport
These youngsters are the most vulnerable to the loss of financial support, she says, with practical barriers such as the cost of bus fares being enough to deter applicants.
"We know of students who cannot afford to get to college," says Ms McMillan.
The survey has been trying to gauge the impact of the removal of the EMA, which had provided up to £30 per week in means tested support for students.
It found that the scrapping of the allowance was cited by colleges as the biggest single reason for a fall in numbers.
Ms McMillan says that the loss of the EMA does seem to have put off the poorest students.
"For people with very little, any extra cost is too much," she said.
What worries her now is the lack of an effective support system to replace EMA.
"While the loss of the EMA might not have been a complete surprise, what has been a surprise has been the lack of an adequate replacement," she says.
In her own college, she says that the EMA could provide students with about £1,000 per year - but now there is only £152 per year available for students who would have qualified for EMA.