Many teachers who take vocational lessons in schools do not know enough about their subjects, a report will claim later this year.
Research carried out for the City and Guilds exam board suggests there are significant weaknesses in the way teachers are trained to teach vocational subjects, particularly in schools.
An early summary of the report says: "Many of those who are teaching do not themselves have a sufficient grounding in, and knowledge of, their subjects."
The Office for Standards in Education said last year that similar problems existed with lecturers in further education colleges.
Inspectors found that while their training was good, lecturers were unable to spend enough time developing their skills once they had a job. City and Guilds says its research suggests that the situation may be even worse with teachers taking vocational subjects in secondary schools.
It says: "These findings are relevant because they suggest that similar weaknesses would be even more apparent among those expected to deliver a more vocationally-orientated curriculum in schools.
"If we are to avoid some of the weaknesses of early general national vocational qualification teaching, when, for example, geography teachers were assumed to have the necessary credentials and background to teach leisure and tourism, it will be necessary to grasp the nettle and ensure that we have sufficient teaching capability with more directly relevant knowledge and experience."
The research, expected to be published in late spring, has been carried out by Professors Michael Young and Michael Barnett of London university's institute of education and Professor Lorna Unwin of Leicester university.
Highlights from it were disclosed in a submission by City and Guilds to the Commons education select committee, which is studying the national skills strategy for 14 to 19-year-olds.
The Geographical Association said there were many examples of schools in which geography teachers had switched to teaching leisure and tourism with excellent results, such as St Ivo school in Huntingdon, Cambridgeshire, where the teachers were praised by inspectors.
However, Dr David Lambert, chief executive of the association, said he shared the researchers' concerns about the lack of in-service training.
"The initial teacher training can be fantastic, but teachers need to develop their subject knowledge in-service and they are often not given enough time," he said. "This is not just a matter for vocational subjects, it is a matter for so-called traditional subjects as well."
The Department for Education and Skills said it was already working to improve standards of initial teacher training in response to the recent Ofsted reports.
A DfES spokesman added: "Curriculum teams are also working with teachers in all parts of the learning and skills sector to ensure that effective teaching is built into subject delivery."
FE Focus 1