The clinical director of BreastCheck has said it will be 'months' before the screening service is back to normal.
Professor Ann O'Doherty said there are 'huge challenges' in resuming services.
She told Newstalk Breakfast: "It's going to take some months - remember all the clinical services in the hospital have lost three months of activity.
"We have huge backlogs in the symptomatic service, we've looked after patients with urgent symptoms.
"But... even though we've done more urgent clinics than normal, we still have many less cancers in my hospital than we would normally would have in May.
"So there are a lot of women out there with lumps who are afraid at the moment, and we're encouraging them to come in.
"And the other thing is for us to do our work now it takes twice as long to do half the work.
"So we're nothing like as productive as we would be in the normal environment."
"We're a long way in all our clinical services - in the hospitals, in all our cancer care - we have to catch up."
She said: "During the start of the COVID epidemic, about two weeks beforehand, we were all absolutely terrified.
"We were making sure that the hospitals were empty, we didn't generate any unnecessary surgery and we were conscious that screening healthy women and bringing them into the hospital during an epidemic was not a good idea.
"A lot of our women are up towards 69 - the age at which [they] should be cocooning".
"The first week of the pandemic all of our staff were in and we were looking after those women.
"Then the next thing was there were women with lumps who we couldn't look after in the hospitals.
"So we actually changed, for the first time ever since the foundation of the screening programme, to look after women with symptoms.
"So that's what we've been doing all through that".
She explained: "While screening is absolutely vital, it's healthy women and if women come for screening we can reduce the number of women dying in this country by 20%."
"But as against that, there is a risk to healthy women - so it's a matter of balancing risk and productivity".
She added: "The bottom line is our doors are open for anybody with symptoms... we're doing our very best. We will get back to screening as soon as we possibly can".