New Zealand captain Daniel Vettori knows his side must improve their death bowling if they are to be successful against Australia.

In their second one-day international against Bangladesh, which the Black Caps won by five wickets for an unassailable 2-0 series lead, New Zealand's bowling attack was plundered for 92 runs in the final 10 overs as the visitors went from 91 for six to 183 for eight.

Daryl Tuffey and Ian Butler bore the brunt of it, although short boundaries at University Oval and the fact Bangladesh took their powerplay in the 45th over also contributed.

Tuffey's final three overs went for 35 runs to blow his figures out to one for 55 from nine overs, while Butler conceded 33 runs in his last three overs - including 17 off the last six deliveries of the innings - to finish with three for 45 off 10.

While the hosts earned a comfortable five-wicket win after reaching 185 for five in 27.3 overs to take an unassailable 2-0 lead in the three-match series, Vettori admitted the bowling in the latter stages of an innings needed to improve.

"It's about execution. Obviously the size of the boundaries made it a little bit more difficult," he said. "But I think we missed a little bit too much.

"If we want to compete against Australia it's an area of our game we've got to make sure is almost perfect otherwise it's difficult to stop very good teams."

Bangladesh were reeling at 46 for six before Mushfiqur Rahim (86) and Naeem Islam (43) gave the score some respectability with a record 101-run stand for the seventh wicket.

When asked if he thought New Zealand had let the visitors off the hook, Vettori replied: "I don't think you can describe bowling a team out for 180 as letting them off the hook. I'm pretty happy with that performance.

"People are allowed to play and there's a couple of decent batters there. They played very slowly and they didn't take any risks and on a flat wicket."

Ross Taylor produced another fine batting effort to score the bulk of New Zealand's runs. His 52-ball 78 included six boundaries and five sixes.

But just when he looked set to get New Zealand across the line with only five runs required he holed out to Mahmudullah in the deep.

"I would have liked to have finished it off at the end but I'm happy with the way it's been going and hopefully I can continue with it," the big-hitting right-hander said.

"I've been working on using my feet a little bit more to the spinners. I'm still a while away yet but with the short straight boundaries it was good to utilise that."

Bangladesh captain Shakib Al Hasan was left to rue another poor batting display.

"Every day someone is getting a start and someone is getting runs but we need three or four guys to score runs to get a good total and that's not been happening," he said.

"(At 25 for five) we were a bit down and we thought there might be a very low score but Mushfiqur and Naeem played very well.

"They put up a 100-plus-run partnership and I thought that was a positive sign for us but we lost too many early wickets in our innings."

The final one-dayer takes place in Christchurch on Thursday.