The Ministry of Economic Development says international tourists are spending less per visit because of the extremely high New Zealand dollar in relation to other currencies.
Figures issued by the ministry show that spending by international visitors dropped by 6.5% to $5.6 billion in the year to June.
The biggest drop in spending was just over 24% by Japanese tourists.
Spending by British and American tourists dropped by 18% and 14%, respectively, but spending by Korean and Chinese tourist increased.
The ministry says significant events such as the Christchurch earthquake and the Chilean ash cloud did not cause a large fall in spending as expected.