Having suffered two heavy defeats from two thus far on their tour to New Zealand, Kyle Mills knows Zimbabwe will be determined to turn things around in the second ODI in Whangarei on Monday.

Brendan Taylor's men lost the one-off Test by massive innings and 301 runs inside of three days and then fell 91 runs short in the first 50-over game of the series. With their visitors struggling, the momentum is certainly with the Black Caps but Mills is well aware that the situation could change very quickly.

"There's no doubt they are going to come back a lot better, harder and stronger in Whangarei," Mills told Fairfax NZ News.

"That's the general theme in most series around the world. The waters are tested in the first game but as the series progresses, both teams get a better read on each other and what they're trying to do and get a better understanding of individual strengths and weaknesses."

"It's a must-win game for them and they did that up in the series in Zimbabwe as well - they progressively got better," he added.

"It's really important we stay on our game in Whangarei because there's no doubt they will be a lot stronger and mentally prepared for it."