The 33-year-old played in all five Ashes Test matches this winter, but was dropped for the one-day series and then left out of the squad for the Twenty20 World Cup, in which England lost to the Netherlands on Monday.
That embarrassing defeat did nothing to strengthen Giles's claims that he is the right man to be in charge of the Test team following Andy Flower's repositioning in the aftermath of the disastrous tour to Australia.
Carberry has added fuel to the fire by condemning the limited-overs coach's man-management skills, citing his being unable to explain why the Hampshire batsman has been overlooked for selection.
"It's that age-old word, man-management," he told reporters. "I had a brief chat with Ashley during the fifth ODI in Adelaide. His response was that he didn't really know. If you don't know mate, I sure as hell won't know.
"Leaving Adelaide after our brief chat I've got to be honest, it didn't fill me with a great deal of optimism. I feel that this is a question he should have answered. And, OK, if it's not him answering, it should be one of the selectors. But that's the way England like to do things. It disappoints me because I'm quite an approachable guy.
"I'm sitting here disappointed I'm not involved in the one-day set-up. I seem to have been left out for some unknown reason. I don't think it's a cricket reason because my one-day stats speak for themselves over the last few seasons. So I'm disappointed the selectors haven't fronted up and spoken to me."
Giles has been England's one-day coach since November 2012.