The White Ferns have won eight of the past 11 Trans Tasman clashes in the shortest format of the game leading into Saturday's match at North Sydney Oval.
Three successive series have gone New Zealand's way, with the most recent clinched when Australia were skittled for 66 in Adelaide 18 months ago.
Australia have held sway in recent one-day internationals but Tiffen is proud her team have found a winning formula in the shorter format.
"In T20 definitely. Over the last few years we've been quite successful against them," she said.
"But I know that that's hurt them," said Tiffen.
"Both teams are back to zero and we're under no illusion that this is not going to be an easy-beat team."
The teams are using the series to prepare for the World T20 in the West Indies.
There will be more at stake when they meet in pool play in Guyana on November 13.
Matches in Canberra and Brisbane next week will complete the warm-up series, which will be Amy Satterthwaite's first as White Ferns captain.
Satterthwaite took charge when veteran opener Suzie Bates surprisingly relinquished the leadership earlier this month.
Bates feels her third-ranked team needed a change after they lost all three T20 matches to hosts and world No.2 England in a mid-year tri-series.
Tiffen said top-ranked Australia will be good enough to expose New Zealand weaknesses.
"They've got experienced campaigners in there like Meg Lanning and Ellyse Perry and they're injecting some youth into their side," she said.
"They've got a huge amount of depth, a higher competition for places and they're ranked No.1 in the world for a reason."