After three rounds, Judkins was tied with Mathew McLean (Harewood) on 216, two shots head of third-placed Jonny Mackay (Timaru), formerly from Oamaru.
The next two places went to Southland representatives with Tyler McLean and Mat Tautari tied on 220.
Simon Boland (Winton) continued his stranglehold on the masters (over-40) event, scoring 72 and 75 to take the title by an impressive 11 shots.
Inia Logan (Cromwell) and Mackay shared an early lead with Auckland schoolboy Archie Gothard with 70. The trio were one shot ahead of Judkins and The Hills professional Craig Palmer.
Gothard (The Grande) carded a 72 in the second round to take a three-shot lead from Mackay, Tautari and Palmer.
Scott Manyweathers (Harewood) and Joshua Bai (Akarana) were within striking distance, four shots off the pace with one round to play.
Otago's top golfers face a busy week with the national intercollegiate final at Cromwell tomorrow while the under-19 boys and girls championships will be held at Cromwell and Millbrook respectively.
The next trial tournament will be held on the Wanaka course next weekend.
