Abortion rates in New Zealand have been steadily decreasing since 2003, Stats NZ said on Tuesday.

While slightly more terminations were performed in 2017 than the previous year, the procedure has become less common in the last 15 years.

A total of 13,285 induced abortions were performed around the country in 2017, compared with 12,823 in 2016.

Eighteen percent of all known pregnancies in New Zealand ended in abortion during 2017. Women between the ages of 20 and 24 were most likely to have abortions, with 21 terminations per 1000 women in that age range.

Fifty-four percent of all abortions carried out in 2017 were for women in their 20s, and 64 percent were a woman's first termination.

It's a significant drop from 2003 when abortion rates were at their highest - 18,510 pregnancies were terminated that year.

Family Planning chief executive Jackie Edmond told Newshub that New Zealand is following an international trend: women in developed countries are simply having fewer abortions.

She says the increased availability of more reliable contraception options is possibly the most significant reason behind the falling abortion rate.

"Things like implants, IUDs have a lower failure rate because they take out the human failure possibility of pills and condoms," she says.

"That's had a significant impact."

She also says young people are better informed about sex than they used to be, and are in general having sex later than earlier generations.

"There's no great research that confirms it, but that's what we've surmised about the lower abortion rates."

Ms Edmond says if abortion were fully legalised there would be little to no impact on termination statistics, contrary to popular belief that making abortion more accessible makes it more common.

"It makes absolutely no sense that it's in the Crimes Act in 2018."

Newshub.