Director of Nursing with the Marie Keating Foundation has urged women to be aware of their bodies and to know what is normal for them and what is not.
Helen Forristal said this was important to be able to identify any changes in relation to appearance of the breasts.
"That in itself means looking at your body and testing and checking it out," she said.
Her advice comes following the death of Girls Aloud singer Sarah Harding from breast cancer.
Ms Harding, who released her memoir earlier this year, revealed her cancer diagnosis in an Instagram post last year, admitting that she did not see her doctor because of her worries over Covid-19.
She had found a lump under her arm and said she thought it was a cyst before her diagnosis.
Speaking on RTÉ’s Morning Ireland, Ms Forristal said changes or symptoms that women should look out for in their breasts are: is one is bigger than the other, any puckering or dimpling in the skin tone, if any veins are sticking out that normally would not and any redness in the skin.
Specifically in relation to nipples, Ms Forristal said to check for redness, swelling and if there is any changes to the direction of the nipple.
When checking yourself she said: "It is very important to check across the collar bone and deep into the arm pit because breast cancer can spread regionally to those parts of the body."
Ms Forristal said the message to check your breasts was not just for older women, but for younger women and girls as well.
"I would say once children reach puberty and the body starts changing they need to notice that and need to start examining their breasts," she said.