Tauranga's Judith Butler, 61, said it was "fantastic", as the more mammograms women were having, the more breast cancers would be picked up before it was too late.
Butler, who is the coach of Tauranga's breast cancer survivors' dragon boating team the Boobops, had been diagnosed with breast cancer twice.
"When I was 40, I found a lump, and then the second time [at 53] was just a routine mammogram."
The first time she underwent radiation and chemotherapy, and the second she had a mastectomy and reconstruction. She said support from friends and family helped get her through, as did joining the Boobops team.
Rotorua breast cancer survivor Lisa Beamsley said the extension would be "really good", but in her view, it should be free for everybody - "from a menstruating young woman until you die".
"The more people that can be breast screened more often is positive in my eyes," the 54-year-old said.
The election promise was made on October 4 by National's Health spokesman Dr Shane Reti and Women's spokeswoman Nicola Grigg.
Currently, Kiwi women between 45 and 69 years of age can receive a free mammogram every two years through the Government's BreastScreen Aotearoa programme if they meet several criteria.
These include having no breast cancer symptoms, not being pregnant or breastfeeding, not having had a mammogram from another provider in the last year and being eligible for public health services.
"Extending the breast cancer screening age will mean that over a lifetime, the number of free mammograms a woman can have will increase from 18 to 20," Reti said.
"This will have the potential to save up to 65 lives per year."
Breast Cancer Support Service Tauranga Trust service manager Helen Alice said the extension would be "absolutely overdue".
"I think previous governments have also pledged to extend it and it just hasn't happened yet. And I understand that there's probably a whole lot of reasons for that, but it's absolutely overdue, and it's been happening in the UK and other places."
Australia, France and the United Kingdom are among those with free breast cancer screenings for women up to 74.
Cancer Society New Zealand co-medical director Dr Kate Gregory said it was "pleasing" to see the policy announcement, as it had advocated for the increase.
"There is clear evidence that women in their 70s will benefit from this, and this policy would prevent breast cancer deaths."
A Te Whatu Ora – Health New Zealand national screening unit spokesperson said New Zealand provided free breast screening each year to about 270,000 asymptomatic women.
Extending the breast screening programme to 74 was "a significant change" and needed to be introduced in a way that maintained the quality of the screening programme.
The programme needed to build capacity in specialist workforces, extend facilities and equipment, and upgrade the supporting information system.
Work was being done to consider how the sector could manage such an increase.
The spokesperson said it was committed to improving access to healthcare, including breast screening services and funding to upgrade the BreastScreen Aotearoa information technology system that was announced in Budget 2021.
The technology enhancement was under way and was "critical" for making safe changes to the screening programme, including to the screening age range.
Women who have not had a recent screen should contact their health clinic or BreastScreen Aotearoa. Women concerned about their breast health should see their doctor as soon as possible.
Health Minister Andrew Little was approached for comment.