Wearing Australian colours for the first time since the ball-tampering scandal erupted in Cape Town in March, 2018, Smith and Warner were greeted warmly by a small crowd in Brisbane, where Aaron Finch's team took a one-wicket win.
Former vice captain Warner, batting at number three behind openers Finch and Usman Khawaja, suffered a nervous start and was dropped in the gully when yet to score in the unofficial match.
However, he soon warmed to the task and hammered six fours and a six in his 43-ball knock before top-edging a reverse sweep to be caught in close.
Warner's knock, coupled with Khawaja's cheap dismissal for four, is likely to fuel the debate as to Australia's ideal opening partnership for their World Cup title defence in England.
Batting at four, former skipper Smith was less assured with the bat, scoring 22 off 43 balls, but made an early impression in the field when he dived for a superb one-handed catch to remove Tom Latham for 13 off the bowling of Jason Behrendorff.
Set 216 for victory after bowling New Zealand out in 46.1 overs, Australia's tail-enders held their nerve to close out the win, with Adam Zampa (11 not out) bringing up the winning runs with a four at 48.2 overs.
Australia seamers Pat Cummins, Behrendorff and Nathan Coulter-Nile all took three wickets against New Zealand, who were missing regular skipper Kane Williamson, Martin Guptill and Trent Boult because of Indian Premier League commitments.
Pace spearhead Mitchell Starc and all-rounder Glenn Maxwell were rested for the first of the three unofficial warm-ups against New Zealand.
Smith and Warner, whose ball-tampering bans were lifted in late March, have been included in Australia's World Cup squad and rejoined their team mates for a training camp in Brisbane on Friday.
Although stripped of their leadership titles, head coach Justin Langer has said they will remain important mentors in Finch's side.
Australia play their first World Cup match against Afghanistan on June 1 in Bristol.
(Reporting by Ian Ransom; Editing by Nick Mulvenney)
