They believe insufficient attention is given to the needs of adults.
Their views were published in a report produced by City and Guilds, the national awarding body, which sponsored a survey carried out by the National Skills Forum and Associate Parliamentary Skills Group.
Vincent Cable, the Liberal Democrat treasury spokesman, said: "The focus of government policy is almost entirely on 16 to 19, which is completely wrong.
"The issue is how to provide new skills or training capabilities for the post-45s and post-50s."
In the report Tim Boswell, a former Tory FE spokesman, suggested that education maintenance allowances should be extended to older learners.
Gordon Marsden, the Labour MP who chairs the Associate Parliamentary Skills Group, said: "We should not forget the skills needs of adults, especially in light of changing demographic trends and the increasing demand for lifelong skills and learning. Adults can be disadvantaged by work-based learning in terms of age restrictions on apprenticeships, together with a squeeze on funding."
The report, Skills: A Parliamentary Perspective, is based on the replies of 78 MPs who responded to questionnaires sent to all English constituencies, and follow-up interviews with 20 MPs.
Chris Humphries, director general of City and Guilds, said: "What they don't do is address the issue of where the resources will come from."
Another gripe of many MPs, revealed in the research, is that even they do not understand the myriad of agencies, acronyms and policies which make up "the learning and skills sector".
Mr Humphries said gobbledygook was a major reason why MPs "recoil with horror" when asked to engage in debate about skills training.
Flora Alexander, author of the report, said: "The skills sector is crying out for simplification. This would help MPs and the general public understand the various initiatives and how they can benefit individuals and employers."