Ireland endured a humiliating 6-1 defeat to Germany on Friday to compound a feeling of discontent left over from a disappointing European Championship campaign.
Lawrenson, who won 39 caps for Ireland, believes that Trapattoni's time is long overdue as boss.
He told The Mirror: "Giovanni Trapattoni should have been sacked in the summer.
"It's been obvious since the European Championships that he'd reached his sell-by date.
"That 6-1 humiliation at the hands of the Germans was a watershed moment. Not just because of the manner of the defeat means as far as his position is concerned, he just looks a dead man walking."