Mercer NZ managing director Martin Lewington said the survey was one time when dropping on an index was not a bad thing.
"Wellington's and Auckland's small drop in rankings is down to exchange rates and the strength of the US dollar compared to the New Zealand.
"The results mean ex-pats' dollars will go further in New Zealand than they would in say Shanghai, so we become more attractive for global talent."
The results of the index were promising for companies looking at establishing headquarters in the country or relocating expats, Mr Lewington said.
It was also important to remember there were other factors which made make this part of the world an attractive hub to access growth markets, including our living conditions, culture and security, he said.
Across the Tasman, Australian cities experienced some of the most dramatic falls in this year's survey.
Sydney, currently ranked Australia's most expensive city for expatriates, dropped 17 places to the 26th most expensive city.
Melbourne, Perth, Brisbane, Canberra and Adelaide also experienced falls.
Mercer spokesman Ed Hannibal said rankings were affected by recent world events including economic and political upheavals - which resulted in currency fluctuations, cost inflation for goods and services, and volatility in accommodation prices.
While Luanda and N'Djamena - ranked as the two most expensive cities in the survey - were relatively inexpensive cities, they were costly for expatriates due to the price of imported goods, he said.
"In addition, finding secure living accommodations that meet the standards of expatriates can be challenging and quite costly as well.
"This is generally why some African cities rank high in our survey," Mr Hannibal said.
Top five most expensive cities for ex-pats
* Luanda, Angola
* N'Djamena, Chad
* Hong Kong
* Singapore
* Zurich, Switzerland
Five least expensive cities
* Managua, Nicaragua
* Islamabad, Pakistan
* Bishkek, Kyrgyzstan
* Windhoek, Namibia
* Karachi, Pakistan
