We're working longer, not smarter.

A new report by investment firm JB-Were suggests New Zealand is in a productivity recession.

Investment strategist and report author Bernard Doyle told Mike Hosking the economy's expanded but not because we're being more productive.

"Ever since the turn of the century the economy has expanded 50 percent but over half of that is purely from population growth and another chunk of that is from working longer hours."

He said the construction sector is an example of an industry working long hours, not more productive hours.

"We are just doing things as fast as we can, just to stand still, just to keep up. In that environment are you going to make the best decisions to become a long term, highly productive business and I would argue no."

LISTEN ABOVE AS BERNARD DOYLE SPEAKS WITH MIKE HOSKING