A New Zealand online women's magazine on Thursday defended a breast cancer campaign that encourages young women to submit topless pictures for publication on the Internet.

The www.nzgirl.co.nz website said its fundraising campaign, titled "I've got a lovely pair", was aimed at raising awareness of breast cancer, although critics accused it of trivialising a serious issue.

The publication - which usually concentrates on subjects such as fashion, shopping and cooking - said the campaign briefly crashed its website on Wednesday, as Internet users rushed to view the pictures posted online.

For every 50 photos uploaded, nzgirl has promised to donate 1,000 dollars (750 US) to breast cancer research, encouraging submissions with the slogan "get your tits out for the girls".

Editor Tee Twyford said she was proud of the positive feedback from breast cancer survivors and relatives of those with the illness about the campaign, which is not officially endorsed by any cancer organisation.

Twyford said its goal was to "encourage women to have a stronger relationship with their breasts", increasing the likelihood any health problems would be detected early.

"The strategy behind this was centred on breasts still being a very controversial topic in a fairly conservative country," she said in an online editorial Thursday.

"We need to remember that they are functional, rational, emotional and sexual parts of our bodies that should be celebrated."

The campaign sparked a backlash among some users on the magazine's online forums and generated heated debate on local radio stations.

"I highly doubt nzgirl would put up photos of breast cancer survivors," wrote forum user Bonnie Hartfield.

Others raised concerns young girls would submit pictures, although the website says its main demographic is 18-35-year-old females, with most in their late 20s.

New Zealand Breast Cancer Foundation chief executive Evangelia Henderson told Fairfax Media it did not comment on other people's fundraising practices but it would not consider running a similar campaign itself.