Latest 2013 data released by the New Zealand census office has shown that Kiwis born overseas have hit more than one million persons.
Statistics NZ said more than a quarter of this country's population of 4,242,048 had been born overseas, versus the 22.9 per cent and 19.5 per cent in 2006 and 2001, respectively.
The countries of origin of those born overseas were also seen as more diverse than previously.
Britain still remains the most common overseas country of birth, followed by China, India, Australia, South Africa, Fiji, Samoa, and the Philippines.
"Back in 1961, two-thirds of overseas-born people came from the United Kingdom and Ireland. By 2013, that figure had dropped to just over a quarter,'' general manager 2013 Census Gareth Meech said.
The Asian ethnic group population in New Zealand has also almost doubled over the last 12 years.
"The growing Asian population is reflected by a rise in the number of people identifying with non-Christian religions,'' Mr Meech said.
"The number of people who affiliated with the Hindu religion increased 39.6 per cent since 2006, and Islam grew 27.9 per cent.''
Further, New Zealand has also become more multilingual. About 18.6 per cent of the population in 2013 could speak more than one language, up from 15.8 percent in 2001.
Mr Meech said the large increases were noted in the Hindi and Northern Chinese languages, with the number of Hindi speakers tripling since 2001. Speakers of Northern Chinese languages, such as Mandarin, meantime doubled.
The largest Asian ethnic group remained the Chinese, with 171,400 people but the growth between censuses was just 16.2 per cent. The Filipino population reached 40,000, up from over 11,000 in 2001.
"This kind of information helps organisations, researchers, and community groups better understand the cultural make-up of our society, and how this is changing over time.''