The former TOWIE star liked an Instagram post which said Arthur Collins should be freed from prison.
Collins, who was recently sentenced to 20 years behind bars for an acid attack, is the father of Ferne's baby girl Sunday.
In a screenshot captured by The Sun, Ferne was showing liking a post shared by his brother Tommy Collins from December 21.
It showed the lads hugging on a night out together.
INSTAGRAM/FERNE MCCANN
PA
“Free up my brother, I miss him the most”
Tommy Collins
Tommy captioned it: "Free up my brother, I miss him the post. Merry Xmas."
However a friend close to Ferne said this was an accident insisted Ferne had not meant to like the picture.
They told The Sun Online: "This is nonsense it was clearly was an accident. She was scrolling down her feed and pressed a button by mistake. She was mortified and removed this immediately.
"There was no reason for her to like this post. He has been out of her life for over seven months and has made her feelings perfectly clear and is trying to move on with her life. It was an accident, nothing more."
Ferne McCann flaunts sexy curves
Instagram
INSTAGRAM/FERNE MCCANN
Collins, 25, was injured 14 people when he threw cid at terrified clubbers at a London nightclub in April last year.
Ferne has previously stated she wants nothing to do with Collins.
She told Sunday People: "I strongly feel for the innocent people hurt that night and I in no way condone violence as I have already made clear."
INSTAGRAM/FERNE MCCANN
A representative for Ferne also previously stated: "Ferne's thoughts are of course with the innocent people caught up in the events at Mangle last April. No one should ever be faced with violence on a night out.
"Having given birth days ago, Ferne is focusing on being the best mother she can be. She long ago accepted that she would be doing this alone and is determined to provide the best possible future for her daughter."
A representative for Ferne has been contacted by Daily Star Online.