Stewart knows the Sharks will be a tough test given the number of South Africa internationals they have in their squad, with nine World Cup winners named in their starting line-up for Saturday.
But after facing a Leinster side stacked with Ireland internationals last weekend, he hopes Ulster will be prepared for the challenge ahead.
“It’s nice playing Ireland one week and South Africa the next!” he joked.
“We’re delighted to be back at home and take it to them. There are opportunities there to go at them, they’re a big pack and they’ll want to go at us.
“They have a good scrum and a good maul, but it’s a challenge we’re excited for.”
Stewart still harbours ambitions of getting back into the Ireland squad after missing out on the Six Nations amid an injury-wrecked season that has restricted his game time at Kingspan Stadium.
Now back fully fit, some good displays in Ulster’s last three games will surely put him in contention for the squad to take on Georgia and Portugal in the summer, when so many Irish players are expected to be on British and Irish Lions duty.
“I’d love to get back into a squad but at the minute I don’t have the privilege of that,” he added.
“I just need to keep working at Ulster and keep playing rugby as much as I can because when you go in and out and it’s not as consistent as you want it to be, I do feel rusty at times.
“The biggest thing is just getting out on the pitch and staying out there.”
