"Uncertainty" around the future of AS-levels is the biggest current issue facing secondary schools, Tristram Hunt is due to warn.
In a speech later today, the shadow education secretary is expected to call on the Department for Education (DfE) to write to schools and colleges to inform young people who are already making decisions on the courses they want to take next autumn that different political parties may have differing policies on the future of exams.
Those beginning AS and A-level study next autumn will be starting their courses after the general election and a change in government could mean a change in direction.
Under the current Government, AS-levels have been separated from A-levels to form a qualification in their own right.
But Labour has previously announced that it will "re-couple" the qualifications if they take office after the next general election.
It has also said that it will delay the introduction on reforms to the content and assessment of AS and A-levels so that they are introduced for teaching in schools from September 2017.
Mr Hunt is due to tell the Association of Colleges annual conference in Birmingham: "The uncertainty surrounding the future of AS-level qualifications is the single biggest, real-time issue facing secondary education.
"As pupils decide - as they currently are doing - on the qualifications that they will be studying from September 2015, the Government is failing in its duty to properly inform pupils about the choices open to them and in preparing schools and colleges for the different scenarios following the general election in May.
"The Government's decision to scrap AS-level qualifications as a staging-post to A-level qualifications narrows opportunities and, as Cambridge University has argued, will be bad for social mobility.
"My message to young people is this: Labour will not pursue the Government's policy of scrapping AS-level qualifications as a staging post to full A-level qualifications.
"We will ensure that options are kept open so that young people can progress their studies with the knowledge that they can decide, in-year, which subjects they will pursue.
"Your choices will not have to change, you will be given greater flexibility."
Mr Hunt's comments come just weeks after Cambridge University wrote to schools and colleges urging teachers to continue to offer AS-levels in the wake of the Government's decision to make them a standalone qualification.
The prestigious institution said it "strongly encourages" would-be applicants to take AS-levels in at least three subjects, arguing that the exams are of "significant educational benefit".
A Department of Education spokesman said: "As part of our plan for education we want students to be given the time to study subjects in detail to develop the deep understanding that will prepare them for life in modern Britain.
"By decoupling the AS-level from the A-level, we are ending the routine of automatic, external assessment of students at the end of Year 12. Removing this unnecessary burden from teachers and students means young people will have more time to study the fundamental concepts of a subject rather than sit through an endless treadmill of exams.
"Students will still be able to sit an AS before deciding whether to take a subject at A-level, but will no longer be required to do so by the Government; instead the decision will lie with students and teachers.
"Our reforms are not being rushed - it is right that changes are made as quickly as possible, so that students can benefit from these new reformed qualifications as soon as possible."