Many construction firms have been unable to keep on their apprentices
Nearly 900 apprentices have had their training cut short by employers struggling to cope with recession.
Figures from Skills Development Scotland have revealed the construction industry has been badly hit, with 700 trainees made "redundant".
Industry bodies had warned of a potential skills shortage after new apprentices fell by a third last year.
Construction Skills Scotland said it was working to transfer apprentices to sectors less affected by the downturn.
Director Graeme Ogilvy said: "They are going to look at areas like highways maintenance, land drilling - these more specialist skills.
"Up until now we didn't have a framework for the civils and specialists so now we have a framework. That's why we want to push that sector."
Scotland currently has about 30,000 young people in three or four-year training schemes.
The figures revealed, as of 23 March, 833 people on the Modern Apprentices programme had been made redundant.
Of those, 261 had found alternative employment or training, 439 were looking for this and 133 people had left the programme.
Peter Hughes, chief executive of Scottish Engineering, said apprenticeships must be maintained to avoid a shortage of skilled workers in the future.
"The recession won't last forever," he said.
"Within construction and engineering we have an ageing workforce and we need to replace that particular workforce.
"If we don't start training youngsters now to take their place, we've got a real problem."
Labour called on the Scottish Government to set up a dedicated helpline to assist apprentices who have lost their job.
Leader Iain Gray said: "The system the first minister has put in place to deliver the apprentice guarantee is not working.
"In the face of the economic crisis, young men and women are being made redundant, losing not just their jobs but their chance of a trade."
A Scottish Government spokeswoman insisted all the actions being called for were already being delivered.
She said apprentices facing redundancy could contact the Partnership Action for Continuing Employment (PACE) helpline on 0808 100 1855 for advice and support.