The ‘Strip That Down’ singer has spoken out against Zayn, who quit the band in March 2015 to pursue a solo career.
Since leaving the other boys behind, Zayn has gone on to make numerous negative comments about his time in 1D - something which has clearly annoyed Liam.
During an interview with The Sun’s Bizarre Life podcast, Liam said he can not understand why Zayn feels that way, explaining: “He doesn’t really support the cause.
“If he feels hurt and scorned in some sort of way that I don’t really understand that’s down to him so there we go.
“It is very sad because One Direction was a wonderful, wonderful time in all of our lives. It was like uni but on steroids, it was mad.
“It was so much fun and I don’t understand how you can come out of that experience and say the things that he says sometimes, it doesn’t make any sense to me but there you go.”
Zayn has remained distant from the rest of 1D since his departure, even having a public spat with Louis Tomlinson, after he made a series of digs on Twitter.
Zayn tweeted: “Remember when you had a life and stopped making bitchy comments about mine?”
However, they later seemed to put their differences aside when Zayn publicly reached out to Louis following the death of his mother last December.
Meanwhile, Liam has been busy making a series of revelations about his relationship with Cheryl, hinting they had married during an interview earlier this week.