Plunket Shield front-runners Northern Districts are set to extend their lead after finishing the third day of their match against Canterbury on the verge of victory.
The Knights went into the second half of the competition with a 14-point lead over second-placed Auckland, and that lead is looking likely to lengthen after three days of action.
Northern Districts require a further four wickets in Rangiora with Canterbury still trailing by 299 runs, while Auckland have a fight on their hands to avoid defeat against Wellington.
The Aces have only four wickets in hands at Colin Maiden Park and still need 83 runs to make the visitors bat again, after Wellington opener Josh Brodie scored a maiden double century to help his side to a commanding first innings lead.
The other match of the round in Queenstown is finely balanced, as Central Districts require 192 runs on the final day to win with Otago needing to pick up nine wickets.
ND v Canterbury
Resuming the day on 331-5, Northern Districts added a further 95 runs to their lead to set Canterbury a mammoth chase of 503, with BJ Watling unbeaten on 50 when the Knights declared seven down.
Canterbury made a reasonable start to their chase, with George Worker (54), Peter Fulton (45) and Shanan Stewart (46) all getting set at the crease. But the Wizards needed at least one of those men to make a big score to have any chance of an improbable victory.
Instead, Trent Boult, Brent Arnel and Vettori all chipped in with a brace of wickets as the Knights reduced their opposition to 204-6 at stumps.
That left Northern Districts smelling victory heading into the final day, a similar position Wellington find themselves in against Auckland. The Firebirds are only one spot below their hosts on the competition ladder, and they look set to leapfrog them into second thanks in large to Brodie.
Welligton v Auckland
Wellington resumed on 269-3 in reply to Auckland's 320, and Brodie ensured they quickly overhauled the Aces' total. The 24-year-old opener brought up his double century shortly before lunch, before falling in the first over following the break for 210.
That eight-and-a-half hour knock meant Wellington totalled 479 in their first innings, a lead of 159 over the Aces, with only Bruce Martin (6-187) able to make any inroads.
In reply, Mark Gillespie picked up where he left off in the first innings, snaring Brad Cachopa in the ninth over. That set the tone for Auckland's second turn with the bat, as Gillespie claimed two more wickets to reach eight for the match and reduce the Aces to 76-6 at stumps.
CD v Otago
A couple of friendly declarations and one batting collapse has seen a result very much on the cards in Queenstown, despite losing the entire first day to rain.
Central Districts captain Jamie How reciprocated Derek de Boorder's declaration and called his side's innings to a close on 198-6, 83 runs behind Otago. It proved to be a very wise move as How's bowling attack ripped through the Volts' line-up to dismiss them for just 115, with Zimbabwean Kyle Jarvis the pick of the bowlers with 3-24.
That left the Stags chasing 199 for victory, but Neil Wagner gave his side a hint of hope by trapping Dean Robinson in front for a duck on the last ball of the day.