Wellington student Damian Tait "goofed around" after leaving school but is now serious about gaining IT qualifications.

Damian Tait is glad of the certificate-level IT qualification he completed from Whitireia Polytech in 2014.

He tried a similar qualification when he first left school 10 years ago but says he did not take it seriously. "I goofed around, being a stupid teenager."

He ended up leaving to work at KFC and then Pak 'n Save until, in 2014, he decided he should turn his interest in computers into a qualification. Tait went back to Whitireia and got a lot more out of the certificate. "It was challenging at times but nothing too difficult."

SIMON EDWARDS/FAIRFAX NZ Chris Hipkins said students had been driven out by higher fees and tighter restrictions on student loans.

Tait has now doubled-down taking a degree.

"I picked up several useful skills on the cert course which helped a lot in the first year of the bachelor and to an extent even now on the second year," he said.

Tait, however, is among a diminishing number of students embarking on formal tertiary training. Data released to the Sunday Star-Times shows the number of people studying at tertiary level students has fallen 20 per cent over the past 10 years.

TAO LIN / FAIRFAX NZ Roger McRae, managing director of engineering firm McConnell Dowell, often has to look overseas for talent.

There were 453,000 students enrolled in tertiary institutes in 2005. By 2014, that had fallen to 363,000.

READ MORE: Better-looking students get better grades – but not in online classes: study

Auckland University student receives Trustees Award

Certificate courses at polytech level were particularly hard hit, down 30 per cent since 2008, despite a Government push to get students into trades training with through its fees-free Youth Guarantee and Maori and Pasifika Trades Training schemes.

Labour education spokesman Chris Hipkins says students have been driven out by higher fees and tighter restrictions on student loans.

"A whole generation of New Zealanders received their tertiary education more or less free and now they are reaching retirement age and are reliant on the next generation to pay tax to support that retirement. Now is a good time to invest in the education of the next generation."

There are already massive shortages in many trades and the drop in student numbers will compound the problems, he says.

In the construction industry, the shortage of staff is not just among the most highly-skilled tradespeople but includes people driving trucks and in lower-skill roles. "There is an acute shortage of skills at all levels across many industries."

IT, engineering, teacher education, agriculture and management qualifications recorded big drops. The number of students studying information technology dropped by more than 20 per cent overall while students studying information systems fell by 35 per cent between 2008 and 2014,from 20,580 to 13,200.

Civil engineering, which is on the New Zealand skill-shortage list, lost nearly a quarter of its students. The number studying automotive engineering dropped 40 per cent.

Roger McRae, managing director of engineering firm McConnell Dowell, says the decline in numbers is a recognised problem.

"In my experience, there is generally a lack of engineering graduates in New Zealand, and this affects the talent available at all experience levels," he says.

"As well as seeing insufficient engineering graduates coming out of our universities, New Zealand also loses them when they head away on their OE or in search of higher-paying opportunities overseas. So we often have to look overseas to fill our talent pipeline – frequently to the UK and Ireland, although we recruit people from a number of countries. I'd like to see more engineering graduates from the universities."

Aborists are on the skills shortage list, too, but forestry enrolment numbers dropped 47 per cent between 2008 and 2014.

John Stulen, of the Forest Industry Contractors Association, says New Zealand is now providing much of Australia's forestry training, too. But he says forestry firms are hiring people with degrees in other disciplines as the use of technology became more important.

Across all teacher education, the number of students fell just under 20 per cent.

PPTA president Angela Roberts says there are major problems attracting secondary teachers who could tackle subjects such as maths and science.

A retirement wave is looming as older teachers reach the end of their careers. "If we don't have new teachers coming in, that's a concern."

But Tertiary Education Minister Steven Joyce says much of the decline is driven by a push to focus on higher-level qualifications.

"We've deliberately encouraged a decline in low-value, low-return part-time courses at Levels 1-3 since they peaked under Labour in 2005," he says.

"If Labour wants to go back to the future and churn people repeatedly through low-level qualifications that are of no use to those enrolled then good luck to them."

The number of people opting for on-the-job training, such as apprenticeships, has risen since 2011, Joyce says.

But Hipkins says the affected courses offer value. "Many of these courses lead directly to employment, while others provide vital foundation skills for further study or training in areas like the trades, sciences, social services, and primary industries.

"Some adult learners need those foundation skills before they can attempt more advanced study or training. Some will have left school with few or even no qualifications, and now the door to a second chance is being slammed in their face."

Nine per cent more people are now doing bachelors degrees than in 2008, 13 per cent more are doing honours degrees, and 19 per cent more doing masters degrees.

But compared to 2011, there has been a drop in bachelor, graduate diploma, and doctorate-level enrolments.

Rick Ede, chief executive at Unitec, says the drop in student numbers is largely driven by an improving economy. Those who might have been choosing between studying and working are now finding it easier to get a job.

TOP FIVE DECLINES (across all qualification levels)

Office studies: 54 per cent

Complementary therapies (health): 52 per cent

Forestry studies: 47 per cent

Manufacturing, engineering and technology: 42 per cent

Automotive engineering: 40 per cent