Tourists from China and South Korea are continuing to buoy New Zealand's tourism industry during periods of the economic downturn, the Chilean volcano ash cloud and Christchurch earthquakes, figures from the Ministry of Economic Development show.

And Chinese tourists could soon spend more in New Zealand than U.S. tourists, New Zealand tourism chiefs said.

Spending by international visitors fell by 6.5 percent to 5.6 billion NZ dollars (4.67 billion U.S. dollars) in the year ending June, according to the International Visitors' Survey, the first by the ministry to fully cover the events of Christchurch and Chile's Puyehue-Cordon Caulle volcano.

The drop in spending was consistent with the previous survey covering the year to March, said the ministry's tourism research and evaluation manager, Peter Ellis.

"Spending by international tourists has been dropping for over a year even though the number arriving remains pretty constant," said Ellis.

"One significant reason tourists are spending less per visit still appears to be the extremely high New Zealand dollar in relation to currencies other than the Australian dollar."

The Christchurch earthquakes the last major quake was in June and the havoc caused to international and domestic flights by the Chilean volcano the same month had damaged tourism less than had been feared.

"These adverse events had their main impact during what is always the low tourism season. On an annual basis the arrivals have held up and spending hasn't collapsed."

Spending by British tourists dropped by 18 percent and by U.S. visitor by 14 percent.

Spending by Australians, New Zealand's biggest market, dropped by almost 6 percent as they spent their strong dollar in other markets.

However, spending by South Korean and Chinese tourists continued to rise, with South Koreans accounting for 4 percent of international tourist expenditure in New Zealand, and Chinese for 7 percent.

Tourism New Zealand chief executive Kevin Bowler said spending by visitors from China was up 12.4 percent and from South Korea up 11.5 percent.

"Chinese visitor spending at 410 million NZ dollars is closing in on, and may soon overtake, the value of the United State's 443 million NZ dollars visitor economy."