"Once again, the uncertainty caused by Covid-19 lockdowns has dealt a crushing blow to our fundraising efforts.
"Without more volunteers in these areas, we can't run our street appeal there."
Volunteer area coordinators are needed to oversee the collection sites in those three centres, and additional volunteer collectors are also required across the rest of the Manawatū-Whanganui region.
"By giving up a few hours you'll be making a huge difference in the fight against breast cancer," Rayner said
"The money raised will help to save lives through cutting-edge research, the promotion of early detection and supporting patients through their treatment and recovery."
Area coordinators oversee a small team of collectors and are supplied with all materials required to look after their local sites.
Whanganui's area coordinator, Shirley Forward, said Covid-19 vigilance meant some older volunteers wouldn't be able to take part in the appeal.
"We have been lucky in Whanganui," Forward said.
"Even with our cashless society, people know we are collecting and will carry cash that day.
"One of our regular guys lost his sister to breast cancer, and he collects in her memory.
"I've also got a big, strapping land agent who collects because of his wife. Last year he was even willing to wear a pink wig up and down the [Victoria] Ave for a couple of hours.
"City College has been wonderful as well in their support as well."
Breast cancer is the most common cancer for Kiwi women.
Each year, about 45 women are diagnosed in the Whanganui District Health Board area.
Forward said about 100 volunteers were usually required for the appeal in Whanganui itself.
"We are doing pretty well at the moment, although it's always hard to fill the spot at Pak'nSave.
"It's a bit cold there, and everybody knows it. We've got a very kind soul who'll do it quite happily this time though."
To become an area coordinator, go to pinkribbonvolunteer.org.nz/becoming-area-coordinator
To volunteer for the Pink Ribbon Street Appeal, go to pinkribbonvolunteer.org.nz, email pinkribbon@bcf.org.nz or phone 0508 105 105.