The former Liverpool player only took over the struggling League Two side last month after the sacking of Kevin Nolan.
His team saw their season go from bad to worse in the last game when they were thumped 5-1 to Exeter City last weekend, the game in which Kewell was sent off for arguing with match officials.
"I questioned the handball and you have to change a few other things because we are chasing the game. The eagle-eyed referee sees another handball, gives it to them and they miss it so we are still in it." the former Australian international said.
"Then there was a cross in the box and it was one of those 'does it hit his hand, or does it not?'. The referee says no, we are complaining, they go up the other end and score a goal.
"That was disappointing and that is when I get my marching orders. I said 'well done' to the referee; I said you can see one in the far corner but not one straight in front of you."
Despite the critical commments, Kewell not face any further disciplinary action in the form of fines or a touchline ban.