The proposal was made in a consultative document Equipping Young People for Working Life which looks at the links between schools, industry and business. John Dunford, SHA president, said it would be impossible for pupils to complete the national curriculum within three days.
Mrs Shephard asked in her SHA conference speech: "Can we tackle demotivation and under-achievement by allowing some pupils to experience a different learning environment for a part of their studies? This is something Sir Ron Dearing urged us to explore at Key Stage 4."
Mr Dunford was not totally dismissive. He said the document was right not to attempt to introduce "daft new schemes" but to try to build on current practice - currently almost all secondary pupils spend one or two weeks on job placements.
He said while schools were striving to make links with employers, it was difficult especially in areas with only small firms. "It can be hard. Work and school links are often made through personal contacts which are lost when that person moves on." He said he hoped the Government would provide incentives for businesses to get involved.
Many FE colleges, for example Wirral Metropolitan College in Birkenhead, already take on school-aged children on many courses, from one to four days a week. But there are fears within the FE sector that Sir Ron Dearing's proposals, and the consultative document, could lead to colleges becoming dumping grounds for disaffected pupils.
John Berkley, manager of education and careers for the Rover Group, said work-related learning should be a feature throughout the curriculum. He welcomed the document and said: "Although there is undoubtedly some remarkable good practice, we have a long way to go before a uniformly high standard is assured."