Now they just need the weather to hold so they have a shot at an outright win.
The Volts have dominated most of the opening two days at the University Oval.
They recovered from 60 for four to reach 416 for seven declared.
Max Chu struck a career-high 151 and got great support from his captain Luke Georgeson (80) and Ben Lockrose (72 not out).
The Stags were nicely placed at 176 for two, but they collapsed to be all out for 224.
Lockrose and Danru Ferns teamed up to skittle most of the remainder of the batting lineup.
Otago opted to enforce the follow-on, and Central Districts are 18 without loss in their second dig and trail by 174 runs.
Poor weather is forecast for the next two days and could make a result hard to obtain.
But Otago had the better of the weekend.
They were in an early pickle. The top order folded without making much of an impact.
The visitors had made good use of the new ball and had a firm grip of the reins. Another quick wicket and Otago would have been teetering.
But Chu pushed back with a quality knock. He combined with Troy Johnson (37) in a stand of 60 to give the innings some substance.
But it was the partnership between Chu and Georgeson which helped move the Volts from the caboose to the engine room. They put on 164 and changed the trajectory of the innings.
Chu brought up his third first-class century when he paddled a delivery from Jeetan Patel behind square for a brace shortly before stumps on Saturday.
Otago resumed yesterday morning on 287 for six.
Lockrose clubbed a career-high 72 not out and Chu accelerated through to 151.
Otago secured two early breakthroughs.
Opener Taylor Bettelheim was trapped lbw first ball of the innings by Georgeson.
And Brad Schmulian nicked off for 15. He charged Ferns and made a late decision to play an awkward defensive shot.
Former Otago captain Dean Foxcroft and in-form opener Curtis Heaphy approached their innings differently.
Heaphy (65) was watchful and selective in the deliveries he attacked, whereas Foxcroft had some zones he favoured. He got on to anything short and played the pull shot nicely. He also dispatched some memorable straight drives down the ground.
Foxcroft looked on course for a hundred but got himself into an awful tangle and spooned a catch to Johnson off the bowling of Ferns for 94.
Otago needed that. The pair had added 155 from 237.
It was a little spark which escalated rapidly.
The visitors lost six wickets for 13 runs. Ferns and Lockrose did the damage.
Dane Cleaver (0) made a catastrophic decision to leave a delivery. Josh Clarkson (1) got trapped in front. Will Clark could not keep out a ball which jagged back. Oscar Mabin (6) and Jeetan Patel (0) nicked off.
The decline was dramatic.
Tyler Annand swatted four fours and a six in a tiny act of rebellion at the end.
Lockrose finished with career-best figures of three for 38, and Ferns claimed four for 57.
OTAGO
First innings
J Boyle c Clark b Annand 6
J Cumming c Mabin b Toole 30
T Jones c Schmulian b Annand 10
T Parkes c Clark b Mabin 3
T Johnson c Heaphy b Toole 37
M Chu c Annand b Patel 151
L Georgeson c Cleaver b Annand 80
B Lockrose not out 72
D Ferns not out 6
Extras (1b, 3lb, 9w, 8nb) 21
Total (for 7 dec, 116 overs) 416
Fall: 1-40, 2-10, 3-51, 4-60, 5-120, 6-284, 7-390.
Bowling: J Clarkson 20-2-103-0 (3nb, 5w), R Toole 28-6-88-2 (3nb, 2w), T Annand 24-4-85-3 (1w), O Mabin 13-3-34-1, A Patel 19-1-69-1, D Foxcroft 8-0-14-0, B Schmulian 1-0-3-0, W Clark 3-0-16-0 (2nb, 1w).
CENTRAL DISTRICTS
First innings
T Bettelheim lbw Georgeson 0
C Heaphy c Lockrose b McKay 65
B Schmulian c Chu b Ferns 15
D Foxcroft c Johnson b Ferns 94
D Cleaver b Ferns 0
J Clarkson lbw Lockrose 1
W Clark b Ferns 1
O Mabin c Georgeson b Lockrose 6
A Patel c Georgeson b Lockrose 0
T Annand b McKay 22
R Toole not out 7
Extras (10lb, 2w, 1nb) 13
Total (all out, 61.5 overs) 224
Fall: 1-0, 2-21, 3-176, 4-176, 5-177, 6-178, 8-189, 9-193, 10-224.
Bowling: L Georgeson 11-0-55-1, D Ferns 15-3-57-4, J McKay 11.5-2-47-2 (1nb, 2w), T Hart 7-1-15-0, B Lockrose 16-4-38-3, T Johnson 1-0-2-0.
CENTRAL DISTRICTS
Second innings
C Heaphy not out 10
T Bettelheim not out 8
Extras 0
Total (7 overs) 18
Bowling: J McKay 3-2-4-0, L Georgeson 3-1-8-0, B Lockrose 1-0-6-0.
