Dwyer's main accusation is that Marler, England's loosehead prop, drives into the scrum at an illegal '45-90 degree' angle - rules state that props must drive straight in a scrum - targeting his opposing prop and attempting to pressure the opposition's scrum into rotating out of position, leading to loss of possession or conceding penalties.
England forced four penalties at the scrum against Wales at Twickenham last weekend, one area of clear supremacy over their opponents amid an otherwise demoralising defeat. England have also used the scrum as a platform to inflict painful defeats on Australia, notably when Andrew Sheridan destroyed the Wallaby front row in the World Cup quarter-final in 2007.
The referee for Sunday's crucial game is Romain Poite, a Frenchman noted for his intelligent reading of the scrum.
Dwyer's comments appear a thinly-veiled attempt at influencing Poite, and the former Australia boss also implicated England's other loosehead, Mako Vunipola, saying he and Marler have been taught the tactics by England's forwards coach, Graham Rowntree.
"It must be by design," he said. "Neither of them scrummage square. Both of them angle in. Invariably that is at 45 degrees, but sometimes that ends up being at 90 degrees. Then when I see the opposition being penalised, I find that extremely hard to understand.
"You only have to look back to a couple of years ago and England were loath to start with Marler because even though he was good around the park, his scrummaging was not up to standard. Now we have a situation whereas he is allowed to scrummage at 45-90 degrees, he has become a very good scrummager. I find that impossible to disregard."
But Jonathan Kaplan, the South African former Test referee, added weight to Dwyer's argument by saying on Twitter: "I'd like to see if the England pack square on the loosehead side... just the once."
