International Jimmy Neesham, returning to full fitness after a back injury in Australia in November, hit 65 and Derek de Boorder an unbeaten 50, as Wellington caught up with Auckland at the top of the ladder.
In Napier, Northern Districts thumped hosts Central Districts by a whopping 284 runs.
Left to chase 438 for victory, CD folded at McLean Park, to be dismissed for a paltry 153, of which Dane Cleaver (40) and George Worker (34 not out) contributed the bulk.
Seamer Scott Kuggeleijn was the pick of the ND attack, taking four for 25 in his 13.4 overs, to follow his four for 82 in the first innings. James Baker and Anton Devcich took two wickets apiece, while international pair Tim Southee and Ish Sodhi got one each.
In fifth round games starting on Saturday, table toppers Auckland and Wellington meet at Colin Maiden Park, Otago host ND in Dunedin while CD play Canterbury in Nelson.
Points after four rounds: Wellington and Auckland 60, Canterbury 46, ND 37, CD 25, Otago 19.