Victor Vito and Wellington teammates go undercover to support the Positive Sidelines Initiative to highlight sideline behaviour.

All Black Victor Vito​ and some of his Wellington teammates have gone undercover in an effort to the highlight sideline behaviour at children's rugby matches.

World Cup winner Vito disguised himself with a wig, moustache and sunglasses for the Positive Sidelines Initiative at a match between Avalon and Petone under-13 boys.

He labelled it an eye-opening experience to hear what parents and kids had to say, and was surprised the abuse was happening at such a young age.

SUPPLIED Victor Vito goes undercover as a volunteer referee of an under-13 boys' match in Wellington.

"These kids were only about 10 or 11 and were swearing and giving me heaps. They knew their laws, but it seemed like they thought that gave them the right to tell the ref what to do.

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PHOTOSPORT The real Vito, as most rugby fans would recognise him.

"And that's not the case. The [referees] are volunteers who are giving up their time, and are as important to the game as the players themselves."

The Hurricanes forward had to remind himself to stay professional amid the abuse he was getting on and off the field.

"To be honest, it was quite tough to keep my composure. I wanted to react straight away, so I really did understand what the refs were going through when it happens to them on Saturdays.

SUPPLIED Vito removes his disguise to reveal himself as an undercover referee.

"In the end, I talked to a couple of players, just reminding them they're there to play the game and let me do it. The same thing I've been told in the past too, funnily enough."

In what he calls a throwback to the 80s, Vito​ and fellow Wellington players Reg Goodes, Jason Woodward and Jeffery Toomaga-Allen did away with their youthful appearance to help with the subterfuge.

"Basically I called up Ken Laban to see what he does every day. I looked pretty similar to him," Vito said.

"They put on a few prosthetics, a wig, a moustache, and I had to wear glasses. I'm probably the first referee to run around in sunglasses and a moustache."

When he removed his disguise and revealed who he was, some of them wanted to hide with embarrassment.

"I guess [they felt ashamed as] it was one of their heroes they'd been bagging the whole game.

"I told them, 'Look, don't worry about it, it's nothing personal, but just make sure you appreciate the refs for what they're giving up and just enjoy the game.'

"I think it was a real eye-opener for them too."

Vito, who joins French club La Rochelle after the Super Rugby season, conceded he made some debatable calls, but said the messages coming from the sidelines could be more supportive.

"Everyone knows in rugby there's always going to be dubious calls, but I didn't expect the swear words with the kids around.

"Even though we feel like we are just supporting, we've got to be careful of how we're supporting.

"It's all about positivity. The negativity we can save for our living rooms, but even then I think that's where kids are learning it."