A new report today by the Construction Skills Network suggested the slowdown in the housing market would cut the number of new workers needed every year from a previous average of 88,000 to 42,000 between 2009 and 2013.
But the study added that high value projects such as the London 2012 Olympics, coupled with investment in schools, hospitals and roads, would help the industry grow slightly.
CSN manager Sandra Lilley said: "The current economic climate provides challenges to every business sector, and construction is no different.
"But, despite some high-profile redundancies recently, our growth predictions remain strong and in line with industry and Government forecasts.
"The fact is that we still need over 40,000 new entrants to the industry every year to fulfil some big projects, and that's a significant requirement."
ConstructionSkills chief executive Mark Farrar remained confident about the long-term picture of employment in the sector.
He said: "The indications are clear that the construction industry will continue to flourish in the long-term, and that the workforce will expand beyond the current number of 2.5 million.
"We advise firms to continue training their employees, as this will ensure they have a safe, professional and qualified workforce, putting them in a stronger, more competitive position to win and retain contracts.
"Businesses should protect and seek to improve the quality of their workforce to mark themselves out to potential clients.
"Past experience also shows that some of the experienced workers leaving the industry tend not to come back, and should this happen it may cause major problems for the country to deliver much-needed affordable housing, schools, hospitals and roads."