Kamo started their innings solidly but the leg spin of Kirk Henderson (3 for 18) kept them at bay.
Quicks Rory Anders (3 for 7) and Tom Herman (2 for 15) applied the brakes at the end of their innings, with only Travis Connelly (27) and Hero Singh (20) making it past 20.
Kamo ended up falling 51 runs short of the target.
Onerahi then lined up against Maungakaramea and put in a dominant display to take a 90-run victory.
Roebuck (55) again led with the bat after openers Kurt Benney (28) and Sharkey Antunovich (27) set another solid platform, helping Onerahi to 157 for 4.
Scott Robertson (2 for 22) and Sean Doel (2 for 15) made early inroads for Onerahi as Maungakaramea's innings never got going.
Captain Herman (3 for 3) came in late to roll the tail as Maungakaramea limped to 67 all out.
Meanwhile, City comfortably accounted for Kaipara Flats and followed that with a win over Whangarei Boys' High School First XI.
In the first match, Kaipara Flats' Kevin Forde led the way with the bat, scoring 44, but was a lone figure as City restricted them to 99 for 4 from 20 overs through economical bowling.
James Thompson (21 not out) and Matthew Lobb (22 not out) saw them home with five wickets and 11 balls remaining.
Against WBHS, City made batting look easy as captain and opener Craig Little smashed 54 off just 28 balls to help his side to 169 for 4 from their overs.
Thompson (42 not out) again contributed with the bat as he and Joey Yovich (26 not out) accelerated the run rate at the back end of the innings.
Only Quinn Pooley (21) and Caleb Boswell-Smith (25) provided resistance with the bat for WBHS as they were limited to 92 for 8.
Kieran Nelson (3 for 8) and Yovich (3 for 14) were the best of the bowlers.
In other matches, Maungakaramea's second loss of the day came at the hands of WBHS.
Maungakaramea's batting order was brittle once again as only Dion McCracken (31) and Hamish Kidd (15) made an impact.
The bowling of Caleb Boswell-Smith (4 for 16) and Kurt Oldridge (2-30) limited Maungakaramea to just 90 all out in 18 overs.
Whilst Matt Taylor (2 for 10) opened the bowling well, going at just two and a half runs an over, the lack of runs they were defending made it tough to get the win.
Maungakaramea needed wickets but the partnership of Lewis Miller (32) and Quinn Pooley (40) ensured a comfortable run chase for the high schoolers, eventually reaching their target with 11 balls and six wickets to spare.
Kamo picked up their first win as they beat Kaipara Flats by 15 runs, leaving Kaipara winless after four matches.