The Department for Education (DfE) proposals would raise the level of QTS from a basic entry qualification to a much more demanding certificate of competency.
Ministers have been working with officials on the plan since before Christmas, according to a key adviser to former education secretary Michael Gove. The matter is still being considered under Mr Gove's successor, Nicky Morgan, TES understands.
The plans to overhaul QTS were revealed by Dominic Cummings, Mr Gove's former special adviser. In a blog post, he writes: "Before I left [the DfE at the end of 2013], there were discussions about creating a new version of QTS that would.come after a more substantial period of training than a year (which I think most people now support)."
Mr Cummings claims that Mr Gove, who left the department in July, had planned to announce the proposals in the summer, adding: "There is a plan 95 per cent ready to go sitting on DfE computers."
At present, teachers gain QTS as soon as they finish their initial training. They must then pass a newly qualified teacher (NQT) year if they want to work in the state sector.
Mary Bousted, general secretary of the ATL teaching union, said plans to make QTS more rigorous were worth considering as a way of keeping teachers in the profession.
"The retention rate in teaching is still not good enough and part of that could well be that newly qualified teachers are not getting the support and development they need," she said. "At the moment, QTS doesn't guarantee that you are going to be competent in the profession for the long term."
Simon Barber, principal of Carshalton Boys Sports College in Surrey, was concerned that the changes could be a "hurdle too far" for new recruits. "I would also want to know about the implications for new teachers' salaries: could that act as another hindrance to recruitment?" he added.
Dan Morrow, associate principal at Oasis Academy Isle of Sheppey in Kent, said: "I am very positive about the principles of this because schools have a vested interest to train staff and make the very best of them. The trouble with QTS is sometimes it has become a certification that a course has been completed, rather than a professional standard."
If staff were to receive QTS after a longer time in the classroom and away from university, it would raise the question of who should award the status. "Radical reform to QTS is definitely on the agenda," said Russell Hobby, general secretary of the NAHT headteachers' union. "There is a lot of debate and speculation about a two-year qualification period and a decision needs to be made about who should finally confirm the award.
"There is a strong body of thinking that it should be school-led. Our view is: there should be a driving test model of teacher qualification. The government should focus on the assessment and the standard and should leave a fairly free rein as to how people achieve that standard."
QTS has become controversial ever since ministers allowed free schools and academies to employ teachers without it. The idea behind the move was to give certain state-funded schools the same freedom as private schools to employ unqualified experts. But it triggered a split in the coalition, with deputy prime minister Nick Clegg calling for QTS to be a requirement for teachers in all state-funded schools.
A new, tougher QTS raises the possibility of the status becoming compulsory for all state-funded schools once more.
Mr Cummings claims that the Liberal Democrats initially blocked the plans because Mr Clegg wanted to keep the issue of QTS alive before the general election. A Lib Dem source denied that charge, but confirmed that the party had held discussions with the Conservatives about strengthening QTS.
A DfE spokesman said there were no "immediate plans" to reform teacher qualifications.
Views from the front line
Victoria Hancock, an English teacher at Oasis Academy Isle of Sheppey in Kent, who gained QTS six years ago after completing a PGCE, said: "I think having two years after your initial training before you get QTS is quite a good idea, because as a student you spend a lot of time back at university, away from the classroom, and when you are in school you are always fully supported by your mentor. Your NQT year is actually a bit of a shock."
Ishani Basu, an English and drama teacher at Sutton High School in London, who gained QTS two years ago after training through Teach First, said: "When you've got your QTS, you still have to prove yourself because you have to pass your NQT year as well. If it takes longer to get QTS, the question is, will your school support you throughout that period or will it be a case of sink or swim?"