Older workers appear to be snatching the jobs of young people, says an economist who wants the Government to get a better grip on the way the nation's labour market is working.

"There's a lot of wild and woolly stuff going on that is raising significant question marks over whether the necessary labour supply is available to meet New Zealand's ongoing growth needs," said BNZ economist Stephen Toplis.

Policymakers at the Treasury and the Reserve Bank would need a deep understanding of the labour market to set the ground rules, he said.

There had been a disproportionate rise in the unemployment rate for workers aged 15 to 19, which was now a "staggering" 27.5 per cent, and the next age group - 20 to 24 years - had a rate of 13.5 per cent.

Workers over 25 - who could be seen as a proxy for "skilled workers" - had a rate of just 4.6 per cent.

On average, the youth unemployment rate had been 11.8 percentage points higher than the non-youth rate since 1986, but by March this year the difference was 21.9 percentage points.

Toplis said it was "curious" that despite the relative surge in the youth unemployment rate, the proportion of unemployed people who were youths had actually fallen.

Between the peak in youth employment at the end of 2007 and now there were 50,500 fewer workers in the 15-19-year age group, a fall of 31.6 per cent, even though there had been an increase of 2400 in total number of people employed.

"The oldies are on the march ... it's an oldies takeover," Toplis said.

Over 56,000 people aged over 60 found jobs in the same period, and 41 per cent of them were aged 65 and over.