Bangladesh captain Shakib Al Hasan made familiar promise following his side's another meek surrender in the tri-nation series in New Zealand on Sunday as the all-rounder said the Tigers will keep working to improve their batting.

''Batting is one area we need to improve and will keep on working on it," said Shakib after an eight-wicket defeat against New Zealand in their second match of the series in Christchurch.

Bangladesh only managed to score 137 for eight, courtesy of a late cameo from wicketkeeper-batter Nurul Hasan Sohan. Bangladesh batting once again failed to find the necessary tempo suited for the shortest format of the game.  

"Yes, with the used wicket, the New Zealand spinners bowled well. We started well but we couldn't handle their quality spinners, and we never got any momentum. We have been talking about this, that the top three have to put their hands up and bat till 15-16 overs," he added during the post-match presentation.

Bangladesh skipper, who missed the first game after arriving late in Christchurch, batted at number seven position to score 16 off 16 balls. Shakib explained the reason behind his decision to come down the order.

"I was supposed to bat up but two spinners were bowling and we wanted to have a left-right combination," said the Bangladesh skipper.

"It is hard to keep energy up when you lose two games. But with the World Cup coming up, the next two games will be crucial for us," he continued.

Black Caps leg-spinner Ish Sodhi became the fifth bowler to take 100 T20I wickets, removing top-scorer Najmul Hossain Shanto (33) in his first over to reach the milestone.

Sodhi dismissed Mosaddek Hossain soon afterwards to further halt the Bangladesh's mid-innings momentum, aided by a miserly 2-14 from fellow-spinner Michael Bracewell.

Home skipper Kane Williamson praised his spin pair's accuracy.

"We worked hard and pulled it back with the spin, which was huge for us to keep them to a below-par total," Williamson said.

"Having no pace on the ball was difficult to play if you hit the right length, and our spinners were outstanding," the New Zealand captain added.

Devon Conway later showed why he will be New Zealand's key batter at the T20 World Cup by top-scoring in a comfortable win over Bangladesh.

Conway batted with control for his unbeaten 70 off 51 balls as the Black Caps chased down 137-8 at the Hagley Oval with 13 balls to spare.

So far in the tri-nation tournament, Pakistan lead after the first round of matches, having beaten New Zealand by six wickets and Bangladesh by 21 runs.

All three sides are using the week-long series to fine-tune ahead of the World Cup in Australia this month.

Up next, New Zealand face Pakistan in the next game on Tuesday.