Women seeking preventive mastectomies under new insurance policies should make sure they know exactly how much cover they're entitled to when they sign up, says a consumer research company.

The advice comes after a woman due to undergo a preventive mastectomy on Monday said she was told "at the 11th hour" her insurer would not be covering the full cost of her breast reconstruction.

Preventive mastectomies, which were in the spotlight after actress Angelina Jolie underwent a double mastectomy and had her ovaries removed, are an option for women at risk of developing breast cancer.

In a Facebook post yesterday, Auckland public relations specialist Anna Jobsz said she had arranged to get the mastectomy several weeks ago with cover from Southern Cross Health.


She said she had been under the impression her insurance would also cover a breast reconstruction.

However, two days ago the insurance company sent her a letter saying it would cover only the breast removal and half of the reconstruction.

Since finding this out, Ms Jobsz said she had received contradictory messages from Southern Cross managers about how her case had been handled.

"One said 'Our staff are following protocol not to discuss limits' and another said 'our staff always tell the policy limitations when asked'."

Ms Jobsz said she had been with Southern Cross for 10 years, paid "the highest level of cover" and her signed policy said she had "unlimited surgical limits".

"As one of the first people in New Zealand to undergo this life-saving surgery I struggle to understand how I've been left in this position at the 11th hour," she posted on Facebook.

When approached by the Weekend Herald, Ms Jobsz said she was working on the issue with Southern Cross and did not wish to comment further.

Southern Cross said it could not comment on the case specifically for privacy reasons.


However, a spokeswoman said the prophylactic (preventive) benefit was a lifetime allowance that ranged from $30,000 to $50,000, depending on the member's plan.

Consumer research company Canstar Blue boss Jose George said with any kind of insurance it was essential to ask lots of questions when signing a contract.

"It's about being clear in terms of what you're signing up for, asking the right questions," he said.

"It's about getting clarity up front ... Ask the questions ... so there isn't confusion at a future date."