The 22-year-old only made his international debut last year but the Australian Rugby Union are expecting big things of the promising Queenslander.
"There isn't anything I've seen that makes me doubt his potential to become a world-class prop," McKenzie, who led the Reds to Super 15 glory last month, told AAP.
"He's been developing his tight-head skills for 14 months and there's still plenty of opportunity to improve.
"He's got a good mindset for it, he loves a challenge and he's tough physically and tough mentally which are great attributes for playing in the front-row."
Those sentiments are echoed by Wallaby head coach Robbie Deans who has been delighted with the progress made by Slipper since he handed him his first Test cap against England 13 months ago.
Slipper has impressed his national boss so much since making the step up from a development contract with the Reds at the time of his international bow that Deans put a great deal of emphasis on signing the youngster up to a new long-term deal with the ARU.
"There's no doubt that keeping James was critical," said Deans, after Slipper signed a new contract with the Reds and Wallabies.
"To achieve all that he did last year, off the [limited] background that he'd had, was a testament to his attitude, his belief and his work ethic.
"That he was able to kick on this season with the Reds, even though he had the misfortune to miss out on the finals, was another great indicator for his future.
"He presumes nothing and is prepared to do whatever it takes."
Slipper is currently struggling with an ankle injury that saw him sidelined for the conclusion of the Reds' Super 15 triumph but he is expected back in time for next month's World Cup.
And with Benn Robinson remaining a serious doubt for the global gathering, Slipper could play a vital role in New Zealand.
With less than a week to go until Deans names his World Cup squad on August 18, Slipper is fully focused getting himself fit and putting himself into contention for the final Tri Nations clash with New Zealand in a fortnight's time.
"Working my way back from injury is not something I've had much experience doing, and I haven't enjoyed the process, but it certainly hasn't hurt with the hunger," said the 114kg tight head who is now contracted with the ARU until after the Lions tour.
"Once you've had the taste of something, and then had to go without, it only makes you all the more desperate to have that experience again.
"The spirit within the squad is great and there's plenty of competition for spots. I just can't wait to get back into it all again."