A university lecturer says it's getting more socially acceptable to not have kids

Figures released by this week revealed the number of childless couples is growing.

The number is expected to grow by nearly a quarter of a million by 2038 to 757,000 up from 513,000 in 2013.

University of Canterbury Lecturer Lois Tonkin said a change in society is one reason behind the increase.

"More people are choosing not to have children, and perhaps some of that is just that it is more acceptable to do that then in the past," she said.

However, Tonkin adds that fertility issues could also be a factor.

"Maybe those who have delayed having children for a whole range of reasons find themselves running into difficulties in getting pregnant."