Concert-goers said Liam kept walking off stage between songs at the Manchester Arena gig on Sunday leaving his bandmates to fill the gaps by talking to the crowd.
One said Liam repeatedly appeared to be in the wrong place on stage and during the encore "intentionally" got in front of Louis who pushed him "aggressively" out the way.
Footage taken by Maisie Adam, 21, appears to show Liam struggling to get past Louis, and then pushing him while giving him some stern words.
