Both were named player of the year for their teams. Kasperek also picked up the bowler of the year award.
The White Ferns spinner has been an instrumental member of the squad since transferring to Otago in 2012.
She was Otago's leading wicket-taker in both the one-day and twenty20 tournaments with 13 wickets at 9.61 and eight wickets at 18.87 respectively. Her economy rate in the one-dayers was exceptional at 2.67.
Despite Kasperek's efforts, the Sparks had to settle for fourth place in both competitions.
Duffy, who was also named bowler of the year, was at his best with the white ball this season. He was the second leading wicket-taker in the one-day tournament with 25 wickets at average of 19.40.
His ability to strike at the top of the innings was crucial to Otago's run to the final.
Duffy found success in the twenty20 competition as well. He took 13 wickets at 19.69 and the frugal economy rate of 7.75.
He laboured a little with the red ball, though.
His haul of 17 wickets at an average of 46.82 will have annoyed the right-armer.
The Volts handed out plenty of awards and one of them was a little curious. Brad Wilson was named Super Smash player of the year despite not always being a first-choice selection.
The right-hander also batted extremely deep in the order when selected despite his vast experience at the top of the order. He was able to play some useful cameos and three not-outs boosted his average to 66.50.
But four players scored more runs and arguably Duffy's 13 wickets were of more value.
The award was perhaps a fitting way to send him into retirement, though.
All-rounder Michael Rippon picked up the one-day player of the year for a tremendous campaign. He was not able to take that form into the other formats.
Wicketkeeper-batsman Mitch Rewick eventually went on to score his maiden first-class hundred in the last game of the season. That was enough for him to pick up the rising star award.
Hamish Rutherford was rightly named batsman of the year. He was Otago's leading scorer in all three formats.
The outstanding individual performance award went to Matt Bacon for his 10-wicket haul in Otago's only first-class victory this season, and Nathan Smith was named most valuable player.
Otago Cricket Awards:
Otago Sparks
Fielder of year: Polly Inglis
Rising star: Eden Carson
Batsman of year: Alice Davidson-Richards
Bowler of year: Leigh Kasperek
Cricketer of year: Leigh Kasperek
Otago Volts
Rising star: Mitch Renwick
Super Smash player of year: Brad Wilson
Ford Trophy player of year: Michael Rippon
Plunket Shield player of year: Matt Bacon
Batsman of year: Hamish Rutherford
Bowler of year: Jacob Duffy
Outstanding individual performance: Matt Bacon
Most valuable player: Nathan Smith
Cricketer of year: Jacob Duffy
