But in the Taieri Mouth down my way, I find the turn of Low Tide is the best time, I have been catching dozens at a time on small pearl white softbaits. 1″ and 3″ minnow gulps. lots of fun on light gear.
they sit on the edge of the deeper holes scattered around the mouth.
getting a Nymph down to them may work, they seem to take anything, but i think your best bet would be a weighted wet fly to imitate the smelt and retreve it slowly against the deep edges.
just my thoughts, They are not particularly fussy fish, I have seen them caught easily on wads of paper soaked in sardeen oil. and i have even caught them on 30g silver ticers while targeting salmon.