Aaron Smith: 'If it wasn't a World Cup . . .'

All Blacks halfback Aaron Smith, a proud and extremely excited new father, says nothing but a World Cup could have taken him away from his family's Dunedin home following the birth of his son Luka.

Last Wednesday, Smith's partner, Teagan Voykovich, gave birth to their son on the same day Smith was named in the World Cup squad.

But after saying goodbye to his five-day-old boy on Monday to meet up with the squad, Smith is determined to embrace his opportunity in Japan where the All Blacks will attempt to make history by winning the William Webb Ellis for the third time in a row.

Not surprisingly, the 30-year-old Smith is still a whirlwind of emotions in Hamilton as he prepares for the test against Tonga at Waikato Stadium on Saturday. He also said he was far more focused, fitter and determined now than he was four years ago when he played in his first World Cup, and he'd played about 40 tests by then.

"It was a pretty short stint… but it's changed my world," he said of fatherhood. "I'm really grateful that Teagan is great – she's nice and healthy and our baby boy is amazing and sleeping. On the first night he didn't sleep much. But he's beautiful.

"At the start of the year I had two big things I wanted to achieve this year. It all happened on one day, to be honest – on the 28th of August he was born and I was named in the World Cup squad. It was a brilliant day and a day I'll never forget.

"It's an amazing thing. I'm so happy he's here. When Teagan was pregnant and I was away it was so hard – I couldn't help her with anything. Now… he is here safe and well looked after. It was tough leaving… if it wasn't a World Cup I probably wouldn't have gone away… But I'm excited to be here and excited to be about what we're going to be embarking on in the next couple of months."

Good luck to the coaches and Smith's teammates if they try to curb his enthusiasm this week. The little No 9 is always an energetic character but the recent addition to his family has taken that to a new level and his game could be heading in the same direction as a result.

"He can't hide his smile," assistant coach Ian Foster said of the proud dad.

"The reality of sleepless nights hasn't hit home to him yet but it will. We're excited for him. There's something pretty joyful about having a child and particularly your first one. For him and Teagan it's been pretty special and he timed it quite right so well done to Teagan with that one. He's had a few days at home and he's enjoyed it."

Smith, who has played 86 tests, also revealed that his mind may have been elsewhere in Perth before the recent Bledisloe Cup defeat to the Wallabies.

"The tension I had going into the Bledisloes was hard because Teagan was so close – 37 to 38 weeks – so my head was a little bit in other places at times. When I was in Auckland I felt way better because I was a two-hour flight from home."

It's not certain whether Smith will play Tonga – the selectors may go for a TJ Perenara/Brad Weber partnership – and the same goes for first-five Richie Mo'unga, still under a slight cloud due to a sore shoulder, and midfielder Jack Goodhue, who is recovering from a hamstring strain.

But one suspects Smith won't mind too much either way. He's excited about his opportunity in Japan and his new status as a dad and the feeling he now has a new perspective on life.

"He gives me motivation to train, to try harder now to try to provide for him," he said of Luka. "I'm still buzzing from it."