Lower export earnings and a fall in spending by overseas visitors has caused the current-account deficit to widen.
Official figures show that it rose to $10.5 billion in 2012, or 5% of GDP, its highest level since June 2009.
The current-account balance - a broad measure of the country's dealings with the rest of the world - has been in deficit for nearly 40 years as New Zealand spends more than it earns.
Net foreign liabilities - a measure of what New Zealand owes the rest of the world - rose to $150 billion or 71.7% of GDP last year.
On a quarterly basis, the seasonally adjusted deficit increased to $2.7 billion in the three months to December 2012, from $2.5 billion in the previous quarter, mainly due to foreign-owned firms in New Zealand paying out more in dividends.
The deficit is expected to get worse, mainly because of the modest economic recovery and the demand for imports caused by the Christchurch rebuild.