The Virgin Media star took to the social media platform to denounce those who made the hurtful comments.
“I didn’t think this place could get lower than my expectations but a couple of people accusing me of fake crying over my dead dad has definitely done it,” she tweeted alongside a screenshot of some of the comments.
Muireann, whose father Brendan died in March following a battle with cancer, recently revealed the hurt and pain she felt after testing positive for Covid-19 ahead of her first Christmas without her dad.
However, in the comments, numerous people have backed up Muireann as they slammed the trolls.
“Oh Muireann, you shouldn't have to deal with that,” one person has written.
“Muireann I think you are great. All joking aside I use to listen to you on Today FM, you were a breath of fresh air and one thing I do love about you is your honesty. So don't mind the keyboard warriors they haven't a decent bone in their body. You go girl.”
Another added: “Such cruel unkind people. My heart was broken for you earlier. Just Block them and remember to just focus on the genuine people on Twitter who know how difficult Christmas is going to be without a loved one and feeling Isolated. Hope you're ok. Sending a hug, take care.”
One person suggested that Muireann “Go dark over the Christmas and New Year's. You need to. I hope you are okay.”
But she replied: “I come on here about once every month Liam. I don’t need to go dark. People need to stop being the worst versions of themselves just so tech giants make more €€€.”
Taking to Instagram recently, the Ireland AM presenter said she hasn’t been able to do any of her usual Christmas preparations as she fell ill.
“Hello lovely people. Didn’t get to all my jobs before Christmas like, get the split ends chopped, the nails done or sort the emergency chocolates in case someone calls with a present for you and you don’t have one for them,” she said.
“What I did manage to do was get Covid so, not completely useless.”
Muireann said she has been in isolation for days now.
“[I] just had a confirmed PCR. The guilt is overwhelming. It’s bad enough thinking about having given this to someone, but at Christmas… It’s horrendous.”
Racked with guilt about contracting the virus, the 38-year-old said she feels like the “worst daughter”.
“Not only that but this is our first Christmas without Dad and I feel like the worst daughter.
“It was always gonna be shit but just being there would at least have been something. I was most looking forward to sitting in his chair with a mug of tea, watching his fav, The Quiet Man, whilst Marie played bridge on her iPad. I feel like I’ve failed them and it’s gonna be hard to make up for this."
As thousands of people have tested positive for the virus in the last few days as the Omicron variant spreads rapidly, she said she knows she is not alone.
“I know right now there are people getting positive tests, people who have worked hard to make it home to see family and friends. I’m so sorry, galz.”
“But we persevere. We mask up. We say thank you to the frontline. We don’t forget them when pay talks come around after this pandemic. Because there will, some day, be an after. We be sound.”
“Smile when we can and try not to be arseholes to each other. Much love. Happy Christmas, wherever you’re gonna end up. I hope it’s somewhere nice,” she concluded.