Students must stay in school or work-based training until they are 17 as the education participation age is raised this week.
John Wastnage, skills policy adviser at the British Chamber of Commerce (BCC), said that many employers did not know about the change and where responsibility lies.
"The duty is on the individual and not the employer and I don't think that's been very well communicated," he said.
"Employers don't have a responsibility with regard to raising the participation age. There's a concern that some employers may just decide not to employ 16-year-olds, because they are concerned they have a new duty to make sure they are in training, and that's not the case."
The school leaving age will raise again to 18 in 2015.
Neil Carberry, CBI Director for Employment and Skills policy, said he supports the move to raise the age, but said the Government must ensure the system is set up for everyone to keep developing.
"GCSEs should become more of a staging post on a well-planned journey rather than an end in themselves," Carberry said.
The Government has also announced students aged 16 will no longer be able to drop maths or English unless they have achieved at least a grade C in their GCSEs.
Education secretary Michael Gove said these subjects were the ones "employers demand before all others".
