Taylah, 14, has claimed her second consecutive national crown, winning the 52kg junior female title, while Xavier, 15, bounced back from defeat in last year’s final to win the 54kg cadet male title.
The pair, who now train at Papuni Boxing in Addington, first learned the sport at home, with grandfather Gary Berg giving tips on an old punching bag.
“He was always showing the kids what to do and things like that,” said their mother, Michelle Berg.
“One day Xavier was punching on the boxing bag and he was like ‘we should get him into boxing, get him down to the gym and whatnot’, so it sort of stemmed from there.”
Xavier started training at Rangiora Boxing, with Taylah coming along to watch before eventually trying it herself.
"She never looked back,” Berg said.

“It’s really good. We’ve both improved so much since we’ve come here,” Xavier said.
That improvement paid off at the national championships two weeks ago, where Xavier beat Manawatū’s Boston Hempel in a split decision, and Taylah defeated Emma Deegan, also from Manawatū, by unanimous decision.
“I thought I’d done enough, but sometimes it’s kind of hard with the judges. Sometimes they see stuff that we don’t actually notice,” Xavier said.
Said Taylah: “I felt like I did really well because I've listened to what my coaches recommended me to do, and it’s shown in my fights.”
She said it was special to win alongside her brother for the first time.
“It’s pretty cool, not many siblings do that.”
Smiling Tigers boxers, Ava and Lea Newman, also won gold in the 54kg youth and 50kg junior female titles respectively.
Meanwhile, Riverside boxers celebrated the club’s first national titles in a decade - and the top prize in New Zealand amateur boxing.

Jonty Oorschot, grandson of Riverside founder and former New Zealand trainer Phil Shatford, claimed the 62kg cadet male title.
Harford also received the Jameson Belt, awarded to the most scientific elite boxer at the national championships – considered the pinnacle of New Zealand amateur boxing.
Riverside and Canterbury trainer Devan Campbell was awarded the Joe Thwaites Shield for training the Jameson Belt winner.
Campbell said he felt “honoured” to win the shield.
“I’m only 31, I’ve worked my ass off with Thomas these last few years, knowing what he’s capable of,” he said.
Harford is among a shortlist of boxers competing for a spot at next year’s Commonwealth Games, with national trials scheduled for December.