The council-controlled organisation was established in 2014 to improve economic development.
Visit Whanganui, Business Whanganui and Education Whanganui come under the Whanganui and Partners banner.
The Statistics New Zealand figures showing an increase in guest nights measured only hotels, motels, backpackers and holiday parks.
Ms Cheyne said that as well as that an increasing number of people were staying in Airbnb accommodation and campervans.
Whanganui and Partners' data showed the number of nights spent in holiday houses, baches, bed and breakfasts and Airbnb accommodation was about three times the number of nights spent in commercial accommodation.
Whanganui had 119 listings on the Airbnb site yesterday.Visitors had spiked at the time of the Lions tour, Ms Cheyne said, many of whom would have been in campervans and therefore not counted as part of the Statistics figures.
The Lions tour did not officially kick off until early June, and the latest figures are from May, so many of these visitors would also not be included for that reason.
Freedom camping in campervans or similar vehicles had become increasingly common in Whanganui, which Ms Cheyne said had not been a problem.
"We're a motorhome-friendly city to begin with . . . we've had no need for a bylaw at this point.
"We've still got plenty of spaces and places they can camp and we encourage those who are self-contained to make use of those places.
"Those that aren't self-contained we encourage to go to a camp site."
The council had begun to consider a bylaw on freedom camping, due to be officially debated at next month's meeting, she said. "I'm aware that there's been a few complaints coming into council but they're not numerous at this point."
Whanganui and Partners was in the process of working with the council to prepare a report on local freedom camping.
A sharp increase in international visitors to New Zealand over the past year has increased the pool of potential visitors, but most of Whanganui's visitors are from within New Zealand.
"Only 20 per cent of our visitors are international,"Ms Cheyne said.
"We've seen increasing [international] visitor numbers but increasing domestic numbers as well."
A national perceptions survey organised by the Whanganui District Council showed a change in many Kiwis' attitudes to Whanganui.
The number of people in New Zealand considering visiting Whanganui as a tourist jumped from 35 per cent in 2015 to 48 per cent this year.
There was also an increase in the number of visitors staying overnight and the number of survey respondents able to identify an event associated with Whanganui.
"We have seen a changing reaction to Whanganui, what's available here," Ms Cheyne said.
The number of events held locally early this year may also have increased the number of guest nights.
The Masters Games and the Artists' Open Studios were particular drawcards in February and March.
February's guest night increase was even higher than May's at nearly 17 per cent.
The rise over the year to May 2017 was just 1.7 per cent, which reflected a fall in guest nights in December and January as well as a winter slump last year.
There was a national guest night increase of 7.3 per cent for the month of May, just over half of the monthly growth in Whanganui.
Whanganui's growth was also higher than neighbouring areas such as Palmerston North, where guest nights rose 7.9 per cent.
In Ruapehu and Rangitikei, the growth was 5.5 per cent and 6.4 per cent respectively.
Mark Lithgow of Riverview Motel said occupancy had increased markedly over the past four years, and this year was busier than last year.
"It has been up on last year. In 2016 it went back slightly."
The number of international tourists, particularly those from China, had increased over the past few years, he said.
"Instead of just going to Rotorua and Queenstown, they come to the provinces a lot more as well."
The increase in guest nights was reflected in the latest visitor spending statistics from MBIE, which showed a 28 per cent increase from May last year.
The data showed growth in spending by both international and domestic visitors to Whanganui.
Guest nights Whanganui (% change)
October 2016 + 8.3
November 2016 + 1.3
December 2016 - 4.0
January 2017 - 3.3
February 2017 + 16.7
March 2017 + 3.9
April 2017 + 10.2
May 2017 + 13.1
Tourism spending Whanganui
October 2016 $9m
November 2016 $10m
December 2016 $10m
January 2017 $14m
February 2017 $11m
March 2017 $12m
April 2017 $12m
May 2017 $11m