Lucy Doolan and Sarah Taylor both posted undefeated half-centuries to help the visiting side sweep past Otago's total of 121 for six with almost two overs to spare.
Taylor whacked seven fours in her innings of 57 from 47 deliveries, while Doolan was more circumspect in comparison, scoring 55 from 56 deliveries.
Suzie Bates picked up the only Wellington wicket to fall, bowling Megan Wakefield for a six-ball duck. The White Ferns all-rounder carries a large load in the side. She opened both the batting and bowling and was tidy with the ball, taking one for 14 from three overs, but missed out with the bat.
Fellow opener and captain Katey Martin top-scored for the Sparks with 39 from 46 deliveries but her team-mates were unable to support her.
Kylie Crowley chipped in with 20 and Victoria Abbott (15) and Susie Burrows (12) played useful cameos. But Otago's total was probably 10 to 15 runs short of a more competitive total.
Dee Doughty was the pick of the Wellington bowlers with two for 21 from fours overs while Kelly Sutherland conceded 37 runs from her four-over spell but did pick up the wicket of Lisa Grant.
The teams will meet in a one-day game today and a second twenty/20 match tomorrow. Both games are in Mosgiel.
