Pupils will be able to get revision help from teachers out of school hours by e-mail, in a trial project to be run next year by specialist schools.
Teachers warn about having to answer e-mails out of school hours
A teachers' union has warned that this could add to teachers' workload.
But the government says the project will be voluntary, and some schools already operate such a scheme.
There could be additional pay or time off for teachers to compensate for extra work, it said. And there would be safeguards against "abuses".
A spokesperson for the Department for Education and Skills says that an "e-mentoring" scheme will be tried next year with the Specialist Schools Trust.
This will use e-mail to "support students and answer revision queries by e-mail out of hours".
David Miliband says too often study leave becomes "video-game leave"
"The pilot scheme will be limited to around 15 schools and designed so that it does not add to add to teacher workloads or expose them to potential e-mail abuses," said a DfES spokesperson.
"The trials would be entirely voluntary, with individual teachers volunteering to participate, and schools using the freedoms of workforce reform to manage the trial, perhaps also looking at time off in lieu or additional pay for volunteers."
But the NASUWT teachers' union said the plans would conflict with efforts to give teachers a better work-life balance.
"It is completely unreasonable to expect teachers to be on call, online out of hours," said its general secretary, Chris Keates.
"However, the most serious aspect of this proposal is its potential to leave teachers vulnerable to e-mail harassment and abuse."
But the government said e-mails would be "subject to stringent security arrangements to prevent potential abuses".
"It should be remembered that many schools already use e-mail contact between pupils and teachers for homework and other activities."
This exchange followed comments on Monday from the School Standards Minister, David Miliband, that "study leave" for GCSE pupils could in practice mean "video-game leave".
"While some pupils may benefit from independent home study away from the school, many more would benefit from a structured programme of study and revision at school, before and during the exam period."
The education department said research had shown that GCSE pupils who had a structured revision programme performed better in exams than pupils who had spent their study leave at home.