Gaze, who coached against Simmons at under-18 level in Melbourne and played several seasons alongside Ben's import father Dave at the Melbourne Tigers, was among spectators at LSU's two matches against NBL club Melbourne United.
"He's just a phenomenal talent that continues to even improve on what we all thought was going to be great," Gaze said.
"The evidence we've seen in his first outings with LSU is that the hype around him, which we've heard about through his performances over in the United States, is absolutely justified because he's just an incredible talent.
"His size, his versatility. He's got the size he can defend the bigger guys, his quickness to defend the little guys, he can put the ball on the floor.
"He's got incredible passing skills. When he drives into traffic, he's got good court vision, natural instincts for the game and package all that up in just a freakish athleticism and you can understand why he is such a highly regarded prospect for the NBA."
Simmons, the 2015 male US high school player of the year, is primarily a power forward, but Gaze believed he could also be a quality small forward.
"The three spot (small forward) is well within his capabilities," Gaze said.
"With the way he can put it to the floor...dare I say it and let's not get too far ahead of ourselves, but he's almost Lebron James-like in the way he can bring the ball up the floor, get to the rack, distribute the ball.
"Right now that's something that you could say, as bold a statement as this may sound, he's got that type of capability.
"If he continues to grow, there's no reason why he can't have that type of impact."
Simmons has played a couple of games for the Boomers, but missed this month's Olympic qualifiers against New Zealand because of his LSU commitments.
Gaze has no doubt the Melburnian can mix it at senior international level.
"From the evidence we saw against LSU he is more than ready in my opinion," Gaze said.
"Certainly from what I've seen he has absolutely got the capabilities to not only play, but make a significant contribution to the Australian team."
-AAP