Universities are facing falling enrolments by school leavers, but the number of people learning a trade is booming.
Industry Training Federation (ITF) chief executive Josh Williams said the number of apprentices had bounced back from a slump during the economic downturn, and some industries were near their capacity for new trainees.
"We got down as low as 36,000 [apprentices] back in around 2012. Since then it's been climbing again, and the best estimate we've got is that there's perhaps a little under 45,000 apprentices out there now."
Building and Construction Industry Training Organisation chief executive Ruma Karaitiana said apprentice numbers tended to fall when the economy was slow, and rise when it was strong.
This time, however, the recovery from the low point had been particularly quick, he said.
"We had a real steep climb coming out of the recession. So we went right down to below 5000 apprentices during the recession and now we're hovering just below 10,000 and that's happened much more steeply than it has in the past."
The increase had been driven by the improving economy, combined with the Christchurch rebuild and residential building in Auckland, Mr Karaitiana said.
He said there were a further 2000 building apprentices enrolled through polytechnics, for a total of 12,000, but more were needed.
"That's not enough and it never has been enough, but it is about where we've always peaked.
"And one of our challenges is that the industry has to be capable of absorbing these people to be able to support them and train them."
The Skills Organisation oversees training and apprenticeships in areas including electrical, plumbing, gas fitting and roofing.
Chief executive Garry Fissenden said apprentice numbers last year grew by a third to 7900 and were still rising.
"[In] 2014, sign-ups grew by 27 percent. Last year, they grew by 25 [percent] and I've been looking at year-to-date February. And our year-to-date numbers are pretty consistent between  and .
"For  to be at the same level as  is actually quite amazing. So the numbers are strong."
But Mr Fissenden said there would still be skill shortages in the medium term.
"All the industry associations are saying we will have some skill shortages. Firms didn't start training early enough - takes four years to actually train an electrical apprentice, at least four years for a plumbing apprentice.
"Depending on who you talk to, they're either productive in their second or their third year - so they've got a bit of an unproductive period before they start generating returns for their company," he said.
The industry training organisations for building and construction, and its skills counterpart, said the average age of apprentices was between 24 and 26, but school leavers were an important source of trainees.
The ITF's Mr Williams said industry training organisations were now using their full allocation of $160 million a year in government funding, and expected they would need a further $20 million a year by 2018.