Reduced business investment would also keep New Zealand's capital stock on a lower-than-otherwise path.
"That means, in short, that we can't make as much stuff," he said.
"All else equal, a smaller capital stock implies a lower productive capacity, weaker economic activity, and lower incomes than otherwise."
He said there were no silver bullets to address the problems, although there were a number of things the government could do.
Among the suggestions were to build more houses, take steps to encourage investment, broaden the tax system to include a wealth tax and apply more scrutiny to government spending.
In addition, the report said New Zealand's pension plan needed attention.
"We urgently need to take a good hard look at superannuation settings to make them fairer," he said.
"It's more complicated than just increasing the eligibility age and/or means testing."
- RNZ