A new study by a Washington-based research group has found that by mid-century, the number of Muslims globally will be on par with the number of Christians, for the first time in history.
The Pew Research Center, has studied demographic trends and found that during the next four decades, the number of people who follow Islam will grow faster than any other religion.
The study predicts that if current trends continue, the number of Muslims will grow from 1.6 billion in 2010, to 2.76 billion by 2050.
The growth in those choosing Christianity will grow far slower, rising from 2.17 billion, to 2.76.
The percentage of Christians remains at 31.4 percent, while the percentage of Muslims rises from just over 23 percent (23.2) to almost 30 percent (29.7)
The president of The Federation of New Zealand Islamic Associations, Dr Anwar Ghani, said it was not clear whether the study has taken into account the casualties in the war in Iraq and Syria and now Yemen.
"Wherever you turn in the Muslim world, it seems the number of Muslims are dying in greater numbers than they are producing so if that continues, then those positions seem a bit too high."
The percentage of those who identify as agnostic, atheist or similar, will shrink, from 16 percent to 13 percent of the world's population, or 1.2 billion people.
New Zealand is one of eight countries predicted to have lost its Christian majority by 2050.
In 2010, 57 percent of New Zealanders were Christian, but by 2050, the largest grouping is expected to be those who are unaffiliated, at 45 point one percent of the population.
The Pew Center study shows that in 2010, 34 percent of Muslims were under the age of 15, which leads to projections that as a religion, Islam will grow faster than other religions.
The high fertility rate of Muslim women is another reason for the growth rate of Islam.
Muslim women average 3.1 children each, well above Christians at 2.7 children, Hindu at 2.4 children and Jewish at 2.3 children per woman.
Christianity is predicted to lose the most followers as people switch to other religions or leave the faith entirely.
The study shows that 40 million people are predicted to switch to Christianity, while 106 million are predicted to leave.
The dean of the Holy Trinity Anglican cathedral of Auckland the Very Reverend, Jo Kelly-Moore, said the key message out of the study is also the message of Easter.
"The best conversation is to highlight the need to know our neighbours; to unite across faith, across fences, across cities and nations, that's where this needs to lead us, rather than leaning back and thinking 'what will this mean?' with a suspicious ear, but to prompt us to know our neighbours."