McNamara felt the officials had been unfairly influenced in the build-up to the match, with talk focusing on the referees rather than the players.
Henry Perenara allowed Tony Williams to stay on the field after swinging an arm at Ben Westwood, and moments later denied Tom Briscoe a seemingly legitimate try.
The decisions soured an otherwise absorbing spectacle at Wembley, where a clinical Australia side scored six tries to outdo a spirited England effort, who must now rally for next weekâ€™s crunch game against New Zealand.
McNamara said: â€œWe should be talking about the exploits of the outstanding rugby league players we have in this country at this moment in time.
â€œBut last week all we were speaking about was the referee and how the game was going to be refereed and so on and so on and I think it put a lot of pressure on the guy in the middle this week.
â€œThey were influenced at the start of the week by the Australian team, Tim Sheens and the rest of his staff and the pressure that that referee must have been put under out there, I think heâ€™s wrong.
â€œIt [the Briscoe try] was a poor decision, a wrong decision, as I believe was the decision not to send off Tony Williams. It was a dead set red card, thereâ€™s no two ways about that and they came on the back of each other.
â€œWe will never use it as an excuse, but I do think he was put under unfair pressure.â€
Ryan Hall put England ahead after 11 minutes with a sensational finish, holding off the challenge of Billy Slater, whose shoulder charge put him in hospital with a broken collar bone.
Luke Lewis and Tony Williams gave Australia the lead before Hall scored his second to send the teams in 12-8 at the break.
Further Australian tries from Greg Inglis, Paul Gallen, Darius Boyd and Chris Lawrence punished England, who only managed two scores in reply from Chris Heighington and Jack Reed.
With the second half marred by controversy, Australian coach Tim Sheens felt that his players were responsible for victory rather than any poor officiating.
He said: â€œI think there were a few controversial decisions but at the end of the day I think the players decided the game.
“I think [Williamsâ€™ punch] came off the shoulder, thereâ€™s no doubt it came up off the shoulder but had it been a direct it he could have gone. The kid wasnâ€™t injured, I think the referee knew that.
“That aside it is a test match and thereâ€™s been some pretty good shots over the last couple of games that weâ€™ve played but I donâ€™t think it was a sending off.
“But thatâ€™s me saying it, Iâ€™m the Australian coach. The English crowd probably wanted his blood.
For Briscoeâ€™s try if you look at the lead up pass it was clearly forward. Everyone can scream about it but have a look at the pass prior to it. It was as forward as any pass that was pulled up on the night.â€
But Sheens denied McNamaraâ€™s accusations of unfair pressure being put on the referee.
He said: â€œI didnâ€™t talk about the referee at all. After last weekâ€™s game we were disappointed in that particular game and Iâ€™ve said nothing about this weekâ€™s game. I let the players decide it and I think the players did decide it.â€
England now face New Zealand in a Four Nations decider next week against New Zealand for a chance to play Australia in the final.
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