New figures show spending by tourists is about $1.7 billion a year more than previously thought.
The Ministry of Business, Innovation and Employment's international visitor survey shows overall spending in the year to September was $6.6 billion.
Australia continues to be the country's largest market with visitors spending $2.3 billion while China, the rest of Asia and the United States are also big contributors.
The figures show a large decrease in spending by British visitors, which the ministry says has been a trend since 2005.
It blames economic challenges in Britain and stronger competition in Europe for tourism dollars.