A win in their twenty20 match against Wellington at the University Oval will result in the Sparks securing a home venue for the January 25 final.
A loss, however, would probably mean Otago dropping out of contention. Both Canterbury and Auckland are expected to win their final matches and that would leave all three teams tied on 12 points.
Canterbury has a superior net run rate and would be likely to advance.
Otago's prospects in the one-day competition are far less rosy. With two round-robin matches remaining in that tournament, the Sparks are in third place with 17 points.
Canterbury leads the competition with 33 points and has booked a place in the final, regardless of what happens this weekend.
Auckland is in second place with 27 points and, in all likelihood, will meet Canterbury in the final.
Otago still retains a slim chance of making the final if it can record two bonus-point wins in its final two games and Auckland loses both its fixtures.
That would leave Auckland and Otago tied on points but the Sparks would advance because they would have recorded one more win.
It is a more hopeful than realistic scenario, however. Auckland should be too strong for Central Districts.
The twenty20 competition represents a much stronger opportunity. The Sparks might not have the depth of some of the other teams but their top players are in wonderful form.
Captain Suzie Bates is the leading scorer with 188 runs and Katey Martin is third on the list with 166. Morna Nielsen heads a three-prong spin attack which includes Leigh Kasperek and Emma Campbell.
''We've been pretty lucky with our top three firing and with our slow ball bowlers,'' coach Warren Lees said.
''So we won't go into the game with a lack of confidence or trepidation.''
Australian batsman Nicole Bolton had agreed to play for the Sparks in this round but has not secured a release from Victoria.
''It is a wee bit of a loss, although once you get to this stage loyalty comes into it and you like to stick with what you've got.
''Of course Nic Bolton is a very fine player but it makes the decision easier for me.''
The Sparks have named the same squad which beat Central Districts earlier this month.
Sparks
Remaining games
Friday: v Wellington, twenty20, University Oval
Saturday: v Wellington, one-dayer, University Oval
Sunday: v Wellington, one-dayer, Brooklands Park
Sparks: Suzie Bates (captain), Polly Inglis, Leigh Kasperek, Katie Martin, Victoria Abbott, Caitlin Blakely, Morna Nielsen, Millie Cowan, Emma Campbell, Megan Gibbs, Georgia Clarke, Bella James.
