Effective this morning, the 3.79% rate is the lowest two-year on offer in the market, alongside HSBC Premier, which is not available through mortgage advisers.
BNZ has also taken the decision to lower its two-year rate for investors to 4.04%. The rate cut indicates investor borrowing below 4% may not be too far away.
The other big four banks could be forced to follow suit as the 2019 price war shows no sign of slowing. ANZ, Westpac, and ASB's two-year specials are currently 3.85% along with the likes of Kiwibank, SBS, Sovereign and TSB.
The central bank is widely expected to cut the Official Cash Rate next month due to slow economic growth, and a growing number of banks believe a third cut is possible in November.
Westpac, in its latest weekly commentary, says a third rate cut to 1% in November is "increasingly likely". However, it believes rising house price growth will discourage the RBNZ from making the cut.
Westpac economists believe three year rates offer the best value in the current market, though it expects "opportunities to fix at an even lower rate might emerge". The bank believes interest rates will eventually increase from 2020 onwards.