Brown, who is in his fourth season in Super League and will take over at St Helens next year, was scathing of McNamara's decision to give New Zealand-born stand-off Rangi Chase his England cap in last year's Four Nations Series. And he is equally critical of the call-up of Catalan Dragons' Australia-raised hooker Ian Henderson for this year's internationals.
He said: "If something looks like a duck, quacks like a duck, it's a duck, isn't it? He looks Aussie and talks Aussie, so I suppose he is an Aussie."
McNamara also risked criticism last year for selecting Sydney-born forward Chris Heighington and Queensland-raised centre Jack Reed, who added more overseas accents to the England training camp.
Brown was surprised over the omission from McNamara's elite training squad of Giants hooker Luke Robinson, who postponed his wedding in 2010 to go on the Four Nations trip to Australia and New Zealand and was arguably England's best player.
The 27-year-old Robinson has also been in good form this year and was man of the match in Huddersfield's 50-14 win over London Broncos in Sunday's Carnegie Challenge Cup quarter-final.
Brown also echoed the disappointment of Castleford coach Ian Millward, another Australian, over the non-selection of promising 21-year-old hooker Daryl Clark in either of the national squads.
"Robbo went to Australia and got player of the tour," said Brown. "Then he was man of the match in the Exiles game but didn't get picked after that. I feel sorry for him, especially when they put an Aussie ahead of him.
"Ian Henderson is an Australian. He is not a Pommie. Rangi Chase is a good bloke and a good friend of mine. But Rangi Chase says 'bro' and has got Maori tattoos. That's because he is a Kiwi, he's not English.
"When you have good young players in England playing well, like Daz Clark, they should be selected in my opinion."