Bangladesh lead the series 1-0 after their bowlers ran riot in the opening match last Wednesday, paving the way to a five-wicket victory in Napier.
It was the visitors’ first T20 win over the Black Caps in New Zealand.
Having put the Black Caps into bat under overcast skies at Mount Maunganui on Friday, Bangladesh struck early when opener Finn Allen was caught in the second over with New Zealand on nine for one.
Tim Seifert smashed 43 off 23 balls before being caught to end his second-wicket partnership of 49 with Daryl Mitchell before rain started to fall.
Bangladesh may seal their first series win in New Zealand in any format on Sunday when the third and final T20 is also held at Mount Maunganui.