South Africa's Sharks secured a spot in Super Rugby's quarter-finals after running in six tries to overpower the Sunwolves of Japan 40-29 at King's Park on Friday.

The win moves the Durban-based side to 43 points from 15 matches to claim the third quarter-final spot from the African groups with an unassailable six-point advantage over the Bulls.

The Sharks will be seeded eighth for the quarter-finals, which means they will face the team that finishes top in the overall standings, either compatriots the Lions or the Chiefs from New Zealand.

Their opponents will be decided on Saturday. The Sharks' tries were scored by prop Coenie Oosthuizen, wing Lwazi Mvovo, JP Pietersen, centre Andre Esterhuizen, flyhalf Garth April and replacement fullback Curwin Bosch.

The Sunvolves, who finished bottom of the combined Super Rugby standings in their first season, were in the contest for much of the match and crossed the line through scrumhalf Kaito Shigeno and hooker Takeshi Kizu and two tries from powerful centre Mifiposeti Paea.

The Sharks effectively won the match at the start of each half.

They scored two tries in the opening seven minutes of the first period when Oosthuizen and Mvovo went in under the posts.

The Sharks weathered a spirited comeback from the Japanese side that reduced their lead to a slender 21-19 advantage at the break, but scored immediately after halftime through Esterhuizen in the corner before adding two more late on.

"It was a good performance from us, the most important thing was to qualify for the playoffs," Sharks captain Pietersen said. "We pride ourselves on defence and we let in some soft tries today. It's something we will have to fix on Monday."