The Young Wallabies could not stem a tide of black jerseys as they were overwhelmed 62-17 by New Zealand in the final of the junior world rugby championship.

The New Zealanders scored seven tries in a sublime display in Rosario, Argentina on Monday, extending their perfect winning record to 15 matches since the under-20 event began in 2008, combining the previous under-19 and under-21 tournaments.

With an entirely different starting team from the 2009 champions, New Zealand scored a try after 33 seconds and led 22-3 after as many minutes during a first quarter in which first-time finalist Australia barely touched the ball.

Winger Telusa Veainu scored three tries and flyhalf and captain Tyler Bleyendaal tallied 28 points before limping off in the final, but it was winger Julian Savea who, even though he didn't get on the scoresheet, was named player of the tournament and junior player of the year.

The Young Wallabies stuck to their task and running gameplan and were rewarded with two late tries to fullback Luke Morahan and centre Kimami Sitauti.

The final score was tough for the Australians who fielded the youngest squad at the tournament and toppled England 28-16 in a hard-fought semi-final after crushing South Africa 42-25 four days earlier to finish top of their pool.

Coach David Nucifora said he hoped his players would learn a lot from the experience, especially with 11 of the squad eligible to compete again next year.

"It's been a really good tournament from our boys and it's a pity it will be overshadowed by that performance," Nucifora said.

"At the start of the game it was pretty obvious the team that could win possession and retain possession and nail their opportunities would win.

We made too many unforced errors and gave away soft turnovers and were unable to control the ball for long.

"This tournament's about learning, we have learned a lot over five weeks, and tonight was the best lesson of all.

"Tonight will be valuable if the boys learn from this experience."

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