TravelBird chief executive Steven Klooster said it was important to confront the growing problem of over-tourism, which is the motivation for creating the index.
"We undertook this study as the first step towards a more sustainable future," Klooster said.
"It's a call-to-action to ourselves and to fellow tour operators, residents and local governments in those places worst affected by over-tourism, to work together to find solutions."
Steve Armitage, general manager of destination at Auckland Tourism, Events & Economic Development (Ateed) said it was great to see Auckland ranked as the most welcoming city in Oceania.
"Like other parts of New Zealand, Auckland's visitor economy is booming. With the boom has come pressure on infrastructure, which has the potential to impact on the visitor experience," Armitage said.
"There needs to be a careful balance between encouraging the growth of tourism in Auckland, so that it's sustainable and doesn't impact on Auckland's natural environment and the experience our visitors have here.
"We are looking for ways we can make the most of tourism, and protect and enhance our environment for future generations."
Barcelona in Spain was found to be the city worst affected by over-tourism, followed by Mumbai in India, Amsterdam in the Netherlands, Venice and Hanoi in Vietnam.
Mexico City, Milan, Sao Paulo, Budapest and Bucharest in Romania were also found to be some of the worst-hit cities by over-tourism. Doha in Qatar, Manama in Bahrain, Lima in Peru, Rotterdam and Kathmandu in Nepal have the lowest levels of over-tourism.
Based on individual factors, Singapore scored the best for port of entry, Abu Dhabi was found to be the safest city in the index, Oslo in Norway was found to be the happiest city and Dublin scored the highest for English proficiency.
Paris was found to be the city most willing to open its homes to tourists.
Top 10 friendliest cities
1. Singapore, Singapore
2. Stockholm, Sweden
3. Helsinki, Finland
4. San Francisco, US
5. Rotterdam, Netherlands
6. Lisbon, Portugal
7. Tokyo, Japan
8. Oslo, Norway
9. Zurich, Switzerland
10. Orlando, United States
Cities most affected by over-tourism
1. Barcelona, Spain
2. Mumbai, India
3. Amsterdam, Netherlands
4. Venice, Italy
5. Hanoi, Vietnam
6. Mexico City, Mexico
7. Milan, Italy
8. Sao Paulo, Brazil
9. Budapest, Hungary
10. Bucharest, Romania