Australia have bowed out in the semi-finals of the under-20 rugby world championship in Japan, going down 31-17 to defending title-holders New Zealand in Tokyo.

Australia led 14-7 early in the second half but two tries in the space of a minute swung the momentum the New Zealanders' way.

NZ centre Shaun Treeby dragged his team level in the 50th minute after flopping on the ball when skipper Aaron Cruden charged down a clearing kick from his opposite Richard Kingi.

Hurricanes winger Zac Guildford then edged the New Zealanders ahead when he sprinted 45m for his second try of the match after a chip ahead from five-eighth Cruden bounced kindly into his hands.

Australian halfback Kingi kept his team in the contest with a penalty midway through the second half, before NZ fullback Robbie Robinson made the game safe for the reigning champions with a 55th minute try.

Earlier, the teams could not be separated at halftime when the scores were locked at 7-7.

Guildford opened the scoring with his first try in the ninth minute when he was given an unimpeded passage to the line by Robinson, who splintered the Australian defence with a decisive break on the short side.

Australia responded 11 minutes later when captain and hooker Damian Fitzpatrick burrowed over.

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