Set a target of 203 for a series-levelling victory, New Zealand batsmen failed to eke together a solid partnership at the top of the order, before falling short, finishing at 195 for eight from its allotted fifty overs.
Tiffen was well on course to take the Kiwis home but her fall in the 48th over spelled the doomsay for the visitors. Earlier, taking first strike after calling the coin correctly, Australia rode on skipper Belinda Clark's 38 and Karen Rolton's 31 to help a Australia post a total of 202.
For the Kiwis, Rebecca Steele was the pick of the White Ferns bowlers returing figures of 1-26 from her 10 overs.
The three-match series is serving as preparation for the World Cup beginning in South Africa from March 22. The third and final ODI will played in Perth on Sunday.