A University of Otago survey of tourists in Milford Sound has found surging visitor numbers haven't affected the overall level of satisfaction, with almost 90 per cent of them highly recommending the destination to others.
But about half of those surveyed were slightly annoyed by the numbers of tourists, vehicles and noise.
In the year to the end of June 767,722 people visited Milford Sound - up 14 per cent on the previous 12 months.
For the same period the previous year 671,191 visited, an increase of 14.38 per cent.
Jeff Grant, chairman of Milford Sound Tourism, said his organisation commissioned the research because of a perception of crowding.
"We wanted to find out how much truth there was in this and develop a survey instrument that could monitor the visitor experience in the future."
The survey included responses from 365 visitors from 22 nationalities.
Milford Sound Tourism, previously called Milford Sound Development Authority (MDA), owns and runs the visitor infrastructure in the sound, including the visitor terminal, harbour, wharves, walkway, public toilets, bus and car parks and airport.
It says its infrastructure is holding up well although carparks were overcrowded about 20 days a year.
Otago marketing professor Juergen Gnoth said results from the survey gave confidence that these visitor numbers were not yet at a critical threshold.
While about half of those surveyed were slightly annoyed by tourism fallout, 78 per cent said they "truly felt the wilderness and natural quiet".
The survey found that those travelling in by bus were significantly less affected by tourist numbers than those visiting by car.
Just on 80 per cent rated their trip through the National Park highly and 91 per cent of all visitors bought a boat tour.
The Milford Sound experience was judged most favourably by those from the United States,followed by Australians and New Zealanders, Europeans and lastly visitors from Asian countries.