Two one-hour shows entertaining hoards of excitable pre-schoolers would be enough to wear out the hardiest of adults, but it's all in a day's work for Hi5 member Tim Harding.

Obviously he's very fit, as one has to be if one is on the road for up to eight months of the year.

The five young Australians, beloved by millions of youngsters (and many a harassed parent), are in New Zealand on a circuit which regularly takes them through Asia, Britain and Australia.

And when they're not on the road, they spend three months of the year recording a new series of shows and building up the Hi5 merchandise empire of albums and videos.

It's a pressure cooker lifestyle which Tim and his colleagues have been living for the last six years, and he admits it was "quite hard in the beginning" coming to grips with their different personalities, but now they all get on.

"We're really like siblings. We've just learned to love each other and support each other though all of this. I think in the last year it's been really nice to really begin to appreciate each other and what we all contribute to the group."

Australian children's shows are on a roll. Frontrunners were the Wiggles, who scored a licensing deal with Disney two years ago and reportedly made the group multi-millionaires.

With Hi5, the creators had some very definite goals. They wanted a show that was strongly educational but with catchy tunes and choreography more akin to a pop group than Playschool.

And they wanted performers who would come across as "big brothers or sisters," rather than teacher-types.

When he successfully auditioned in 1998, then 20-year-old Tim was playing in a jazz band at night and studying to be a social worker by day. He thought the Hi5 formula was a winner.

"Our creator at the time realised that more and more pre-school kids were getting into things like the Spice Girls and S-Club 7."

He does an imitation of a toddler singing a Spice Girls number.

"I was working in a childcare centre and that's what I saw all the time."

While none of the group had a background in early childhood education, they all had to have a rapport with children.

Tim had worked in childcare, Nathan Foley had helped younger children through talent schools and quests, and the three female members of the Hi5 crew -- Charli Robinson, Kellie Hoggart and Kathleen De Leon -- had either taught dance, done kids' parties or youth work.

Each performer has a special niche -- music, movement, linguistics, visual spatial, and maths -- and each segment is followed with a dance which reinforces the previous idea to help children with learning difficulties.

The show has become more successful than anyone imagined.

By the end of this year, it is estimated the group will have performed to nearly 1.5 million people.

Hi5 is mobbed in Singapore and won several Australian music and television awards.

British kids are going to Hi5 fitness classes, and American and Hindi clones of Hi5 mean the show can reach parts of the world the Australian cast has no time to get to.

Rather diplomatically, Tim says he has no idea how much the Hi5 franchise is worth but he knows the show is watched in 82 countries.

"It's just out of control," he says.

"We can't believe it."

However, time is marching on. While Hi5's members still have youth on their side -- their ages range from 24 to 30 -- the question which hangs in the air is, how long can the current line-up keep up the pace?

Charli is married and Kathleen about to be. None of the group is a parent yet and life on the road makes children virtually impossible.

"I'd love to be a dad but I just couldn't be," Tim admits.

However, he can see the potential for Hi5 the concept to carry on.

"Providing we can move with the times, I think we'll always be around but having said that, we're not always going to be 'big brothers and sisters'. Pretty soon we'll start turning into parents -- and grandparents!"

Tim says life after Hi5 is "absolutely" imaginable and he's not sure what's ahead.

If the show had not come along, he laughingly reveals he once had dreams of running a surfing camp. "Young people could come to learn to surf.

"I was going to move into youth work and things like that -- so I'd probably be sitting somewhere on the coast of New South Wales being a surf bum."

Hi5's New Zealand tour visits several locations in the South and North islands, ending in Auckland on January 30.