Education leaders are to lobby the Government for extra funding for students' travel costs.
The council spends an average of £800 per pupil
Northumberland County Council wants more help for students aged over 16, especially those in remote rural areas.
It spends £1.8m a year for school transport but is increasing pre-paid fares from £220 to £250 this year to meet a rise in bus fares.
The council is also due to meet the Learning and Skills Council to look at the pressures on students.
Council leader Michael Davey said: "We hate to have to pass these costs on to the students, but we simply do not have the money to meet them fully, especially at a time when the general trend in education is increasing numbers of students staying on into the sixth form.
"We have been extremely generous compared to other authorities up until September, whereas most other councils charged."
The council provided free transport for students over 16 until September 2003.
It spends an average of £800 per pupil, rising to £1,000 in rural parts of the country.
If a student pays £250, it says it is still subsidising the bulk of their fare.
The Education Maintenance Allowance scheme operates in Northumberland, to provide help with education costs for families earning less than £30,000 a year.
The Learning and Skills Council also issues funds to colleges to support students.
Mr Davey said: "The present system does not recognise the pressures facing students in rural areas with further to travel.
"We at the county council will make our case to central government as well as working alongside the LSC."