The difference between what the country earns and spends internationally has hit its highest level in nine years.
Official figures showed the current account deficit for the year ended September was $10.5 billion from $9.5b in June. In dollar terms that was the biggest since September 2009.
That amounted to 3.6 percent of the value of the economy from 3.3 percent in the previous quarter, and the biggest in five years.
This was caused by a big fall in the surplus on trade and services, while foreign investors earned more from their New Zealand investments.
"The $2.2 billion fall in the goods and services surplus between 2017 and 2018 was the largest contributor to the wider current account deficit for the September 2018 year," said Stats NZ senior manager Peter Dolan.
On a quarterly basis, the actual current account for the three months ended September was a deficit of $6.15b, compared with a deficit of $1.6b in the previous quarter of last year.
However, on a seasonally adjusted basis, which smoothes out one-off events and influences, there was a slightly smaller quarterly deficit of $2.6b.
The balance of payments broadly measured the country's ability to pay its way in the world and how much it needed to borrow.
Westpac senior economist Michael Gordon said the numbers were largely in line with expectations.
"While the current account deficit has widened in recent years, it remains within a sustainable range."
Credit rating agencies watch deficits as a sign of an economy's indebtedness.
The net deficit of the economy's investment liabilities - the difference between what New Zealand has invested overseas and what foreign investors own in New Zealand - remains near its lowest level in nearly 20 years.