As in the past few decades, 72 per cent of marriages in 2019 were first marriages for both partners.
Islam said the increasing population had led to declining marriage rates.
Only 10 couples per 1000 people eligible to marry (unmarried people 16 and over) were married last year - less than half the rate of 30 years ago.
Family First NZ has issued a statement citing a correlation between a decline in marriage rates and an impact on children and families. It warns the drop in marriage rates could have a negative social impact on children, according to recent reports on child abuse and family structure.
"The statistics are clear. Children being raised by their married biological parents are by far the safest from violence – and so too are the adults."
Similar drops have been seen in the UK, Australia, Canada and the US. Despite the drop in marriages, people are still choosing long-term relationships.
The 2018 census showed 61 per cent of New Zealand's adult population was either married or in a de facto relationship.
The data released today includes marriages up to March 2020, but there doesn't seem to be a significant drop in marriages as a result of Covid-19.
Meanwhile, there was a small increase in the number of divorces in 2019 - 8338, up from an average of 8075 over the past five years.
On the other hand, divorces are on a downward trend, as are the chances of a marriage ending in divorce.
Around 20 per cent of marriages in the late 1990s ended in divorce within 10 years, dropping to about 15 per cent for those occurring in the late 2000s.