The General Teaching Council has put off a final decision on whether college lecturers should be allowed to teach in secondary schools.
Mary Rose Caden, the council's convener, told its last meeting that the proposal from the further education committee should be more widely considered by the education and convener's committees.
Hugh Pollock, convener of the FE committee, warned that the new Higher Still courses would significantly increase the level of vocational education for post-16 pupils and school staff would not be qualified to take the courses .
The issue is controversial for the GTC in that employing lecturers in schools would blur the distinctions in registration categories between the different sectors. Mr Pollock denied this was a backdoor attempt to secure compulsory registration for FE lecturers.
He said: "It is in fact the first step through the front door and an essential precondition of school-college partnerships involving FE lecturers in the school environment."
Although the council's school members did not voice opposition at the meeting, teachers are wary of any move that breaches the principle that only qualified secondary teachers should be allowed to teach in secondary schools.
The only exceptions are learning support teachers and cases where repeated attempts to fill a vacancy have been unsuccessful.
David Eaglesham, general secretary of the Scottish Secondary Teachers' Association, said: "We would be very concerned about the distinctive nature of secondary education being eroded. The circumstances in secondary schools are quite different."
But Mr Pollock, assistant principal of Dumfries and Galloway College, said: "There is no threat to the secondary sector from the proposal. It will allow institutions to work more closely together for the benefit of the pupils. " No school in Scotland could offer the full Higher Still curriculum whereas every college could, Mr Pollock added pointedly, so the proposal would in reality reduce any threat to teacher jobs.
The FE committee was suggesting that lecturers should be allowed to teach in secondary schools only "under tightly controlled conditions", Mr Pollock said. Lecturers in a college with which the school was in partnership would teach only subjects for which there was no qualified secondary teacher in the school.
Anne Wilson, general secretary of the Association of Directors of Education in Scotland, told the GTC her colleagues would want a say before the proposals were advanced. The directors did not have a formal position, Mrs Wilson said later, but many may well prefer schools to pursue more general partnerships with the FE sector, allowing pupils to attend college for part of their course, for example.
But the FE committee says its proposals would have the advantages of reducing the need to transport pupils to colleges and ensuring they were able to continue in school for their fifth and sixth years.
The Association of Scottish Colleges says it wants to encourage close relationships between colleges and schools but has yet to formulate an official view.
George Livingstone, education vice-dean at Jordanhill, who is a member of the GTC, told the council the proposals "hold the germ of a positive way forward". But Mr Livingstone said that a system of monitoring would be essential and called for a preliminary "mapping exercise" to match school and FE subjects and qualifications.