Hendry and Canizares fired seven-under-par 65s at the $2million European Tour event at Lake Karrinyup with Englishman Paul Casey amongst the chasing pack after a 67.
Canizares, who is looking for his second Tour win after his 2006 Russian Open success, was a late entry for the Perth event after only deciding to compete following his missed cut in Portugal last week.
"I played pretty steady the whole round and gave myself plenty of chances," the Spaniard said after his bogey free round.
"I think I only missed two greens in the whole round and one of them I chipped in on the eighth hole, par 3, which was a bonus.
"I putted well. I missed a couple short ones on 14 and 15 for birdie, but I made a long one on 17, so I made up for that and made a good one for put on 18," added the world number 246.
Argentina's Emiliano Grillo was one shot back of the leaders after a firing a 66 with Casey and compatriot Andrew Johnston tied for fourth.
Casey, the former world number three, showed no signs of his recent struggles for form as he continues to battle back from a dislocated shoulder suffered in a snowboarding accident last year.
"I played wonderful golf today," Casey, the world number 132, said.
"I thought the golf course would be trickier this afternoon, I have no idea, I wasn't out this morning but I'm going to assume it was slightly trickier this afternoon.
"The greens certainly got a little crispy and I struggled to reach a couple of putts. But tee-to-green was beautiful and I am ecstatic with the number of birdie chances I had," Casey said.
World number 10 Dufner, the best ranked player in the field, matched Schwartzel's 71 and the American Ryder Cup team member was disappointed with his round.
"I mishit a couple of drives and never got it going today," Dufner bemoaned.
While Dufner was downbeat, Schwartzel was optimistic about his chances of registering a first tournament win since his Masters triumph at Augusta.
"Six shots is nothing. There are so many holes to go. It's just the start. You can lose it in the first round but you can't win it," he said.
"I had difficulty judging the swirling wind out there today and you need to pull the right club from the bag to be precise on these sloping greens."