New Zealand's population will reach four million at approximately 5.30pm on April 24, Statistics New Zealand estimated today.
"This is a significant event for New Zealand. It has taken nearly 30 years to reach this milestone, after reaching three million in 1973," government statistician Brian Pink said.
But the population is unlikelyto reach five million unless New Zealand's birth rate or net migration increases, according to latest projections.
The population is expected to peak at 4.81 million in 2046.
Nearly all the population growth from three to four million was due to natural increase -- an excess of births over deaths.
"Migration did not contribute significantly to this growth," Mr Pink said.
Lower birth rates and an ageing population meant the population was likely to grow at a slower pace in the future, he said.
New Zealand reached one million people in 1908 and two million in 1952.
In February, the country was just 24,400 short of four million.
