The first balance of payments surplus in 20 years is helping to stabilise New Zealand's high levels of debt. The balance - the difference between payments by New Zealanders and those from overseas - was last in surplus in 1988.
The deficit equates to 3.1% of gross domestic product; at the start of this year, the figure was 9%. Falling export income outweighed lower import income during the quarter, producing a slightly higher goods trade deficit.
Overall, the seasonally adjusted September balance of payments surplus of $340 million cut the annual deficit to $5.7 billion, which compares with $15.4 billion in the previous year.
A BNZ economist, Craig Ebert, says the surplus should buy time with the credit ratings agencies.
One agency, Fitch, had put the chance of a downgrade at 50% in the two years after May's Budget because of New Zealand's debt levels, which are the third highest in the OECD after Iceland and Hungary.
A downgrade would cost the country hundreds of millions of dollars in higher interest payments.
Statistics New Zealand says the falls are due to the economic recession, with less spending on imports and a decline in company profits.
Provision for payments totalling $1.4 billion from ASB, Westpac and ANZ helped to push the September quarter balance into surplus. The banks made the provisions for tax avoidance, which have contributed to a big fall in the investment income deficit.