While Fleming conceded that all-rounders Ben Stokes and Moeen Ali, as well as wicketkeeper Jonny Bairstow, would cause problems for Australia he was scathing in his assessment of Keaton Jennings, Tom Westley and Dawid Malan.
"England needs three decent batsman in their top six," Fleming, who played 20 Tests and 88 ODIs when Australia were in their pomp in the 1990s, told Melbourne's RSN radio.
"Watching the South African series, they're some of the worst batsmen I've ever seen play Test cricket."
England beat South Africa 3-1 in the just-completed series but Fleming said the retention for the Ashes of opener Jennings and top order batsman Westley would offer plenty of opportunities for the Australian bowlers.
"(Jennings) scored 127 runs at an average of 15. I used to bat nine in Test matches and I would just be happy with that, averaging 15. Just be happy. He's opening the batting," Fleming added.
"I don't like his technique, closed grip, he's going to nick people that can angle the ball across him and bowlers that can actually get the ball to shape back in, that gap between bat and front pad. This is an opening batsman.
"Westley has a similar technique. He is squared up, he has hands that are a long way in front of his body with a closed grip. How does he hit the ball through the off side? He's going to nick off or get in trouble with the ball that comes in.
"Where are 80 per cent of the deliveries going to be to Jennings and Westley? Outside off stump, maybe shaping away. They don't have a technique to cope with that."
Westley and Malan made their test debuts in the third test against the Proteas, with the former taking over at "first drop" from the injured Gary Ballance, who did not escape Fleming's brutal analysis.
"How did Gary Ballance play Test cricket again after that last series two years ago there?" Fleming said, referring to the batsman's axing after two tests of the 2015 Ashes.
"Young Malan, 35 runs at an average of eight. There's real opportunities for Australia to run through the top order."
England, who won the 2015 series 3-2, begin their defence of the Ashes in Brisbane on Nov. 23.
First Published: August 9, 2017, 1:44 PM IST