The Bulls moved into fourth place on the log and the Hurricanes snatched the outright lead from the Crusaders in the most significant developments in the third round of Super 14 matches at the weekend.
All five New Zealand teams won their third round matches, while just one of the five South African and none of the four Australian sides managed a victory.
The Hurricanes continued their perfect start to the season with a 29-16 win at home against the Cats, becoming the only team to complete the first three rounds with a maximum 15 points.
Their South Island neighbours, the Crusaders, also maintained their unbeaten start to the season, but in less convincing fashion with a 22-20 win over the Sharks in Timaru. They missed out on a bonus point to slip a point behind the Hurricanes in the standings.
The Highlanders, who were beaten by the Crusaders in the opening round, made it two wins in a row with a 17-12 win over the Cheetahs in Bloemfontein.
New Zealand's two other teams, the Blues and the Chiefs, registered their first wins of the season against the two Australian sides now propping up the standings.
The Blues eked out a hard-fought 21-20 victory over the Reds in Brisbane, while a second half try by Chiefs fullback Mils Muliaina wrapped up a 26-9 win against the Western Force in Perth.
The ACT Brumbies also remain unbeaten although they slipped five points off the lead after settling for a 15-15 draw with the Stormers in Cape Town.
The Bulls joined the Brumbies on 10 points with a 26-17 victory over the previously unbeaten Waratahs to salvage some pride for South African rugby and complete a miserable weekend for Australia's sides. Despite the sweep of wins and the comparative misfortune of their rivals, several of the New Zealand teams were forced to work hard for their victories.
The Hurricanes needed a last-minute try from fullback Isaia Toeavaalso to secure their bonus points against the Cats and lost captain Rodney So'oialo and lock Paul Tito for next week's fourth round after both were suspended for trampling.
All Blacks flyhalf Dan Carter had to nail a long-range drop-goal seven minutes from time as the Crusaders racked up 16 unanswered points to come from behind and beat the Sharks in Timaru.
Fijian Test fullback Isa Nacewa kicked a penalty six minutes from the end as the Blues beat the Reds by the barest of margins after the Australians had twice taken the lead late in the second half.
And replacement wing Richard Kahui scored a try with three minutes to go to give the Highlanders victory over the Cheetahs in a match played in torrential rain.
The Brumbies claimed a moral victory by scoring two unanswered tries against the Stormers, while the Bulls and Waratahs scored two apiece.