The Central Districts opener scored an undefeated 132 to help his side reach 294 for three in reply to Otago's first-innings total of 352.
It was his third first-class hundred and the 24-year-old right-hander had good support from Will Young (62) and Ross Taylor (48), who looked in terrific form.
Otago had hoped to push on towards 400 yesterday morning but was only able to add a further 22 runs.
Volts coach Nathan King described yesterday's effort as a ''tough day''.
''Day two is always the best day for batting and we know from our first innings that it is a nice wicket to bat on.''
Otago's young new ball attack of Michael Rae and Jack Hunter held their own, though, King said.
''They did a decent job and will learn a lot from having to bowl on a tough wicket which is not offering them a lot and against a couple of decent players.''
King said Smith's innings was chanceless and he played superbly, ticking the scoreboard over while Taylor, in particular, was looking very threatening at the other end.
''Taylor looked very good, actually. He came out with a pretty positive mind-set and looked to play his shots.
''We possibly gave him a couple of loose ones to get him going but we were very lucky we got him when we did because, the way he was going, he could have hit us all round the park.''
Another Black Cap to impress was Central's Doug Bracewell.
He completed his seventh five-wicket bag when he removed both Nick Beard (14) and Adam Miles (15) to help wrap up Otago's innings.
He finished five for 67 and will be feeling confident ahead of New Zealand's tour of Australia.
In Hamilton, Northern Districts strengthened its grip on its game with Wellington.
It has reached 346 for four at Seddon Park and leads Wellington by 79 runs with two days to play.
Daniel Flynn resumed on 53 and went on to post his 18th first-class century, while Black Caps No3 Kane Williamson also spent some quality time in the middle.
He made 65 during a more than three-hour stay at the crease.
The game is advanced at Eden Park No2 with Canterbury 38 for one in its second innings.
Auckland posted 316 in reply to Canterbury's very modest first-innings total of 149.
Colin de Grandhomme (70) and Brad Cachopa (61) made strong contributions, and Tarun Nethula chipped in with an unbeaten 48.
Andrew Ellis was the best of the Canterbury bowlers with three for 54.
