Tourists are spending about $1.7 billion more per year in New Zealand than previously believed.
The International Visitor Survey, with results to the year ending in September, was released today by the Ministry of Business, Innovation and Employment.
It is New Zealand's primary measure of tourists' spend and behaviour and the data is collected year-round and reported quarterly.
The ministry had redeveloped the survey over the past 18 months following calls to improve the sample size, the way the data is collected, and to make the survey easier to complete.
MBIE's manager of Sector Performance Peter Ellis said the changes had revealed international visitor spend had been under-reported.
"The new data show that around $1.7 billion more is being spent per year than initially thought. We've revised historical data to make it comparable so that people can still analyse trends over time."
Spending by visitors to New Zealand has remained fairly constant over the last year at $6.6 billion, with some notable changes, Mr Ellis said.
"There has been a large decrease in the total spend by visitors from the United Kingdom - 23 per cent to the year ended 30 September, 2013. In addition, their average spend has decreased 16 per cent.
"So not only are fewer people from the United Kingdom visiting New Zealand, the visitors that do come here are spending less."
The change was credited to economic challenges in Britain and increasing competition from European markets.
It was also possible historical ties had weakened between here and the UK, Mr Ellis said.
"But that's moving into speculative territory."
The survey showed strong growth in the US market, with the total spend by American visitors increasing by 19 per cent in the year ended 30 September 2013.
Tourism New Zealand said that aligned with more advertising in the Americas as well as the release of first in the Hobbit movie trilogy.
Australia continued to be New Zealand's largest tourism market, with Australian residents spending $2.3 billion while visiting New Zealand in the period.
Changes to the survey include:
• It is now being done online rather than face-to-face with staff retrieving tourists' email addresses after they go through security;
• Queenstown Airport was added as the forth airport to collect data;
• Business lounge passengers were added as respondents in the survey;
• The questionnaire was being shortened from taking 25 minutes to 10 minutes;
• Rather than asking what tourists spent on certain things such as food, accommodation and activities, they are now being asked how much their bank balance or credit card went down during the trip.