The US Open champion beat the Ukrainian sixth seed 6-4, 6-1 to set up a final four clash with either Serena Williams or Czech seventh seed Karolina Pliskova.
It was the 21-year-old's second straight Grand Slam semi-final after her triumph at Flushing Meadows and she is the first Japanese woman in the final four at Melbourne Park since Kimoko Date in 1994.
Svitolina received treatment for a neck or shoulder injury in the second set and looked a shadow of the player that won the WTA Finals in Singapore last October.
"I tried to be consistent, it's unfortunate that she got injured but playing against her even when she was injured was still really tough," Osaka said.
She was pleased to maintain her composure in a simple straight sets win after previously losing her cool on court when her last two matches went to three sets.
"I just had one goal, to try as hard I can and not get angry," she said.
"I didn't do that really well in the last two rounds and I did that today, so I'm really happy with the way I played."
Both players fired down aces to hold their opening service games then went on to exchange two breaks mid-way in the opening set.
Osaka was the dominant player, hitting 17 winners to three and four aces to one but struggled to put away her chances.
She has complained throughout the tournament that she was making too many mistakes and 19 unforced errors to Svitolina's seven in the first set kept the Ukrainian in the match.
Osaka wasted three set point opportunities, screeching in frustration as she sprayed the ball wide on both her forehand and backhand.
She finally converted a fourth opportunity when Svitolina netted a return but looked anxious heading into the second set.
She settled her nerves and took an early break, then held serve with an ace.
With the set at 3-0 in Osaka's favour, Svitolina received treatment for an injury that also hampered her during a three-set fightback against China's Zhang Shuai in the third round.
She struggled when play resumed, conceding a break then limply handing Osaka her seventh straight game in the next to make it 5-0.
She held serve to get on the board in the second set but it only delayed the inevitable as Osaka claimed victory after 72 minutes.
Highlights Tennis Elina Svitolina Australian Open Naomi Osaka