New Zealand have ended England's recent dominance at under-20 world rugby championship level with a 21-16 victory in the final in Cremona, Italy, on Sunday morning (NZ time).

The climax of the 2015 edition was billed as England's forwards against New Zealand's backs, but the Baby Blacks' muscled up to hold England scoreless in the last 20 minutes and withstand the pressure.

In doing so they denied England a third successive under-20 championship title, and returned to the winner's circle for the first time at the annual tournament since 2011, when they were also victorious over England in Italy.

It is New Zealand's fifth triumph since the tournament's inception in 2008 - they won the first four - and follows finishes of second, fourth and third in the previous three editions.

Coach Scott Robertson's team swept through Italy unbeaten, riding a strong forward pack and classy back division through the past three weeks.

"It was a tough arm wrestle and I'm really proud of the boys," Robertson said.

Marco Luzzani Akira Ioane, right, celebrates with his team-mate Vincent Tavae-Aso after scoring the try during New Zealand's 21-16 victory over England in the under-20 rugby world championship final in Cremona, Italy.

"Our scrum and lineout was superb, which is a strength of the English, and we won a tight game. We've got really good character and culture in the group and I'm just really proud. It's been four long years."

Robertson, who has used season-long themes with the Canterbury NPC rugby team, said the Baby Blacks had adopted a war theme while in Italy which was all about fighting hard for the "heroes and fallen before us".

England shot out of the blocks, monstering New Zealand in the early forward exchanges and forcing three ruck turnovers in the first three minutes. That dominance led to the opening try, with second five-eighths Max Clark bursting through the line and dashing 20 metres to score near the posts in the fourth minute.

The respective No 10s, Otere Black for New Zealand and Rory Jennings for England, traded penalties before New Zealand nabbed their first try, a solo effort from replacement back Vince Tavae-Aso in the 26th minute.

The winger had only been on the field for 90 seconds, having replaced second five-eighths TJ Faiane who limped off with a knee injury, when he received an offload from Jack Goodhue, who had moved into the midfield, and scooted 40m to score. Tavae-Aso appeared to have been wrapped up by three England players on the 40m line but he broke free and made a beeline for the corner.

Black added a penalty and New Zealand took an 11-10 lead into the break, and they extended the lead to eight points early in the second half when outstanding No 8 Akira Ioane crashed over from close range, the big Blues loose forward proving unstoppable from 3m out.

Ioane went from hero to villain in the space of two minutes when he was binned for a late and no-arms tackle on Jennings, but it was a poor call from the assistant referee. It was marginally late, at worst, but there were arms used and even just a penalty would have harsh.

New Zealand minimised the damage to two penalties in Ioane's absence, though they were fortunate England butchered a try when replacement back Piers O'Conor crossed the line but replays showed he had positioned himself just in front of Howard Packman when the latter had kicked through for O'Conor to chase.

With about 20 minutes to go, Black pushed the margin back out to five points at 21-16 with his third penalty of the night and their defence did the rest.

"It was very physical and big ups to the boys, they came out and executed the stuff we needed to execute," New Zealand captain Atunaisa Moli said.

"The plan was just to build phases. England played well and put a lot f pressure on us but the boys were great."

New Zealand 21 (Vince Tavae-Aso, Akira Ioane tries; Otere Black con, 3 pen) England 16 (Max Clark try; Rory Jennings con, 3 pen). HT: 11-10.