New Zealand immigration policy is seen as a contributing factor to the current baby boom.

New Zealand is experiencing the biggest baby boom since the 1960s which is putting increased strain on midwives and medical services.

The latest figures from Statistics New Zealand show more than 64,000 live babies were born in New Zealand last year, the most since 1963.

Experts say the buoyant economy is partly behind the rise in births and they believe there is a celebrity influence as well as the demographics of those emigrating to New Zealand.

University of Auckland demographer Dr Ward Friesen says the high birth rate recorded for women in their early thirties may be related to the high levels of migration because immigration is age selective and some women coming into New Zealand may delay having babies until they have migrated.