Devon Conway and Daryl Mitchell struck superb centuries as New Zealand secured an eight-wicket victory over hosts England in the first one-day International in Cardiff on Friday to ramp up their preparations for next month's World Cup in India.

Half-centuries from Dawid Malan, Ben Stokes, Jos Buttler and Liam Livingstone had powered England to 291-6 after being put into bat at Cardiff's Sophia Gardens.

New Zealand's chase got off to a strong start, with Will Young and Henry Nicholls contributing runs, before Conway (111 from 121 balls) and Mitchell (118 from 91) shared a stunning stand of 180.

After both batters brought up their 100s, the duo stepped on the gas and Conway sealed the win in emphatic fashion with a six straight down the ground.

"Pretty happy with way things went, nice to spend time in the middle and get the win," Conway said.

"The communication in the partnerships were great. I always enjoy batting with Daryl, we complement each other well. It made my job easy, just getting him on strike. Long may it continue."

England had started well as Harry Brook (25) and Malan (54) stitched together an opening partnership of 80.

After the openers departed in the span of just five balls, Stokes, who reversed his retirement from ODI cricket ahead of England's title defence at the 50-overs World Cup in India, stepped in to score 52 and keep the momentum going.

Captain Buttler (72) and Livingstone (52) then combined for 77, but after the two were dismissed by Tim Southee in the same over, England's tail was unable to take them past 300.

"Disappointing. Thought we had a pretty good score at halfway... Credit to them, it was a fantastic partnership and we couldn't find a way to break it," Buttler said.

"We tried most things, for a little period we built pressure and pushed the rate to just under seven, but Daryl Mitchell played some big shots and took it away from us. Brilliant partnership."

Though the hosts had some strong batting performances, they lost wickets at regular intervals.

Rachin Ravindra was the pick of New Zealand's bowlers, picking up three wickets for 48, his best figures so far in his fledgling ODI career.

The second match of the four-game series will be played at the Rose Bowl in Southampton on Sunday.