Otago leads by 38 runs with seven second innings wickets in hand having reached 113 for three when bad light forced an early end to day three.
But with the remaining time available in the game, and with some rain forecast, it is unlikely the home team will be able to build a defendable lead.
That means the Volts will show up this morning looking to bat for time and to save the match rather than bat aggressively to set up a chase.
Central, on the hand, will be looking to take Otago's remaining wickets as quickly and cheaply as possible having established a first innings lead of 76 after reaching 222 for nine.
With no play possible on day two, Central resumed day three at 134 for six with van Wyk unbeaten on 40 and Nethula on 23.
The pair came together on Monday with the innings teetering at 74 for six and, with a combination of resolute defence and calculated aggression, they steered their side past Otago's first innings tally.
Van Wyk played a marvellous hand, bringing up what was a gutsy half century.
Earlier, he had dived to make his ground and the grill of his helmet jarred into his face cutting his nose.
But the partnership came to an end when Otago left-arm pace bowler Neil Wagner dug in a short delivery which struck van Wyk on his right hand.
The wicketkeeper-batsman winced and tried to shake off the pain but was forced to retire hurt on 51.
He has broken a bone in his hand but is hopeful the injury will not spell the end of his summer.
Van Wyk's dismissal brought veteran medium pacer Michael Mason to the wicket.
He extracted some revenge on behalf of van Wyk, thrashing three fours in one Wagner over.
At the other end, Tarun Nethula played beautifully to bring up his maiden first-class half century.
He raised the milestone with an exquisite late cut.
He let the pace of an Ian Butler delivery do most of the work, steering the ball between gully and point.
The innings ended disappointingly, though.
The right-hander got a gentle edge off the bowling of Anthony Bullick.
Bullick strained a quadricep earlier in the match and had shortened his run-up to about five or six paces.
Butler, who bowled impressively, cleaned out tail ender Bevan Small to close the innings.
He finished with three for 51 from 12.3 overs and Wagner took three for 75 to take his season tally to 39 wickets.
Otago's second innings got off to a shaky start with promising left-hander Michael Bracewell playing around his pad to be trapped in front for four.
Shaun Haig played a couple of carefree and trademark drives.
One glorious shot raced through the covers for a boundary.
But old habits die hard and he thrust out his front pad and was struck adjacent - the impressive Kieran Noema-Barnett was the bowler this time.
At 28 for two, Otago looked to its two senior statesmen, Craig Cumming and Neil Broom, to correct the ship.
Both were averaging more than 50 for the season at the start of the match and settled into their work nicely.
Cumming had a moment early in his innings.
He got a nick when he was looking to glance the delivery leg side and appeared to have been caught by stand-in keeper Tim Weston.
The umpire Evan Watkin certainly thought so and quickly raised his figure.
But the ball had dropped short and the batsman survived.
Cumming got into stride caressing four lovely drives down the ground, and Broom looked in good touch.
But with the light fading Cumming made a mistake, edging Noema-Barnett one run short of a half century.
Central will feel that dismissal has left the door ajar.
Wellington is close to giving itself a Plunket Shield lifeline as it edges towards victory over Canterbury at Rangiora.
It enters the fourth and final day of the seventh-round fixture today on 105 without loss in its second innings, 150 runs short of securing just its second victory of the season.
Wellington, which began the round in fifth place and 11 points adrift of competition leader Central Districts, earlier dismissed Canterbury for a very respectable 339.
In Hamilton, Northern Districts should inflict Auckland's fifth outright defeat today after again enjoying the better of the contest yesterday.
The visitors ended the third day at Seddon Park on 259 for nine in its second innings, leading overall by only 196 runs.
They began the day disastrously, losing Tim McIntosh for a second ball duck and his opening partner, Jeet Raval, for seven, and thereafter were forced to take a cautious approach after already trailing by 63 runs on the first innings.
