Waitemata Health clinical director of obstetrics Dr Sue Belgrave said some women elected to have a caesarean when they were able to deliver naturally but it was unrealistic to try to meet the WHO target.
"I think the WHO statistics are out of date and I don't think health boards should be driving to that," she said.
"Yes, it's expensive, yes it's bad for our resources and we need to manage it, but I certainly don't believe we can strive for a very low caesarean rate in New Zealand in 2013."
The goal should be to stabilise the number of C-sections and that was being achieved.
Auckland DHB obstetrician and gynaecologist Michelle Wise said women becoming pregnant later in life were more likely than younger women to have medical conditions connected to their pregnancy.
Most elective caesareans were the result of mothers choosing to repeat the operation with second and subsequent children, she said.
"What we're starting to see is a lot of significant complications in multiple repeat caesarean-sections, which have risks that can be quite significant.
Dr Wise said mothers were given "as much information as possible to decide for themselves whether they want to try a vaginal birth or have a repeat caesarean".
A childbirth educator at Mama Maternity Information Services, Brenda Hinton, said she was worried by the trend of women choosing a caesarean believing it was "an easier option".
"If they do see it as an easier option they're being sadly misled," she said.
"I think we live in an age where people like to control all sorts of aspects of their lives.
"It's not easier to have [a caesarean]. The only thing you're avoiding is the unpredictability of labour."
College of Midwives adviser Lesley Dixon said New Zealand's rate of caesarean sections was lower than that of most other developed countries.
"Globally we're not doing that badly as such. However, we could always do better.
"Most women do want a natural birth because clearly it's better for them and better for their baby.
"There's lots of research that shows normal birth is optimal for women and babies, and that caesarean sections have risks that go with them."
Caesarean sections
• 1980: 9 per cent of total births nationally
• 1990: 15 per cent of total births nationally
• 2001: 21 per cent of total births nationally
• 2010: 23 per cent of total births nationally
Source: Ministry of Health
* Read more: Mother disappointed births weren't able to be natural