The children in the study were born between April 2009 and March 2010. The next big wave of data collection will take place when they turn 11 years old - a major transition point as they prepare for secondary school and enter their teenage years.
Growing Up in New Zealand director Susan Morton said the new funding provided certainty for the study for the next three years. In the past, researchers had to reassess what they could do with the available funding every six months.
"It's very good news," Morton said. "Because in the last few years we've had quite a few ups and downs in terms of lengths of funding and continuation."
Growing Up in New Zealand was controversially reduced to around 2000 participants in 2016 after the previous National-led Government reduced its funding.
That raised concerns that the study's past data collection would be undermined - and that the full diversity of New Zealand's young people would not be captured.
But the study was restored to its original number of participants last year when the coalition Government invested another $1.9 million in it.
Morton said it was a "challenging time" but she believed the study had recovered from that period and the data had not been undermined.
The Government has also opened another round of funding, worth $750,000, for research projects which explore and analyse the Growing Up in New Zealand study.
For more on Growing Up in New Zealand:
• Kiwi kids at six years old: Thriving and happy, but with a few concerns
• Ten-year childhood study: Fascinating findings about New Zealand children
• Half of Growing Up in New Zealand preschoolers live in rented homes, with single parents
• Govt accused of gutting major child study