A large decrease in New Zealand's debt to the rest of the world has made the economy less vulnerable to shocks, the Reserve Bank says.
But the level is still relatively high internationally and the saving and investment behaviour of households remains the key risk.
"New Zealand's net foreign liabilities (NFL) - what we owe to the rest of the world, broadly speaking - reached nearly 85 per cent of GDP at the start of 2009," Reserve Bank deputy governor Geoff Bascand said.
"Eight years later, they sit at 58.5 per cent of GDP, their lowest level since the late 1980s," Mr Bascand said.
However, in dollar terms, the value of the net foreign liabilities has not fallen substantially.
It stood at $159 billion in March 2009 and $155b in March 2017.
The decline in New Zealand's net foreign liabilities partly reflected that low global interest rates had reduced the interest payments on the overseas debt, while high equity prices boosted the value of overseas assets, he said.
However, a "better balance" between national saving and investment during the current economic expansion had helped contain the current account deficit and lowered the ratio of net foreign liabilities to GDP.
The central bank is projecting the NFL-GDP to remain at about its current level of just below 60 per cent between now and 2020.
Mr Bascand said if the NFL position reflects an "enduring improvement" in New Zealand's savings-investment balance there are wider impacts.
"If sustained, higher domestic savings relative to investment demands would help lower New Zealand's neutral real interest rate."
Mr Bascand also said one "striking feature" of the improvement is that it has occurred despite the real exchange rate being high over much of the period.
Typically a higher exchange rate would contribute to widening the current account deficit but "the improvement in the NFL-GDP suggests that the exchange rate might be more sustainable than previously assumed," he said.
However, Mr Bascand warned the net foreign liabilities as a share of GDP was still relatively high internationally, especially given the nation's exposure to commodity exports that can be subject to large price swings.
Also, "significant uncertainty remains regarding household behaviour and the contribution of the sector to New Zealand's saving-investment gap, and the extent that banks as intermediaries might increase their reliance on offshore funding," he said.