In Canada the average was 1.5 days, in Australia, the average was two days, and in Venezuela, it took about 230 days to start a business.
New Zealand also ranked No 1 for its ability to lend business credit to its entrepreneurs.
By comparison, the US and Australia each received a rank of four for business lending, while the UK didn't make the list of top 25.
Companies Register data shows more than 40,000 businesses were started up in New Zealand between April and December 2020.
Commentators put this elevated number down to more New Zealanders returning from overseas because of Covid-19.
The university study also praised New Zealand's relatively quick containment of Covid-19, along with the support given to existing businesses compared to other countries.
"This country may also currently be easiest to maintain an existing business, as it has received much praise as the emblematic champion of how to properly deal with the Covid-19 outbreak," the report said.
"This notoriously destroyed many existing businesses in other countries."
Singapore and Hong Kong also both earned incredibly high scores (98.2 each) for ease of starting a business internally.
Singapore lets residents start their businesses online and Hong Kong has invested in communication and transportation which benefit small businesses.
Both countries average just 1.5 days to get a business incorporated or legitimised.
Read the full report here.