Anstiss (Otago) had a faultless 3-under-par 68 in the morning round with three birdies and 15 pars.
He turned 2-under in the afternoon, opening up an impressive lead on the rest of the field.
Duncan Croudis (Otago) celebrated his return from his golf scholarship, finishing in second place with two par rounds, while Brandon Hodgson (Otago) is keen to regain his place in the top quintet after finishing in third place yesterday.
Abigael Crawford (St Clair) took the honours in the women's section with rounds of 77 and 84 in the fine conditions.
Daniel Barnett (Otago), Ryan Bellamy (Port Chalmers) and Tyrone Ratahi (Otago) all showed their intentions, finishing in a tie for fourth on 146.
Three 2013 incumbents, Mark Brooks (Queenstown), Nick Borren and Sean Masters (both Otago), finished in the top 10.
The day got off to a slow start with a 20-minute delay due to heavy fog.
The event was played on Park's alternative layout, with the club's 13th hole becoming No1 for the event.
Otago No1 Brent McEwan (St Clair) was on his honeymoon in Adelaide but will be back in action in Wanaka and Cromwell next weekend.
The busy trial season then goes to Queenstown for 72 holes and to North Otago for another 72-hole event.
