"On an individual operator level, an accommodation provider on the Whanganui River Rd noted much lower numbers of mountain bikers came through in March in comparison to the previous year, this despite the very wet summer of 2016/17. Their 'general' tourism visitors were about the same as previous years. They had no insight as to why there were lower numbers of bikers on the lower Mountains to Sea trail."
Whanganui hosted the New Zealand secondary schools athletics championships in March 2017 which would also have had an impact on the statistics.
Chaplow said the decrease for March was minimal and the overall trend was important.
"The current year to year growth for the Whanganui District visitor spend is +4.1 per cent for domestic visitors and +7.6 per cent for international visitors. This has continued a trend of steady growth which started in 2014.
"A marketing strategy for 2018/19 is being developed over the next two months which will have some new initiatives to ensure that Whanganui continues its tourism growth and contributes to a growing local economy."
For Ruapehu the statistics were healthier, with tourism spending for the month increasing 16 per cent compared with March 2017 to $14 million. The region recorded a 10 per cent increase for the year ended March 2018.
Mark Gordon, MBIE's manager of sector trends, said MBIE developed the tourism estimates in consultation with tourism industry representatives to create a better measurement of the value of tourism in the regions.
"Tourism spending information for the regions helps inform investment and planning in the tourism industry by providing insight into where both domestic and international tourists are spending their money."