The cost of bringing up one child is the same as a brand new Ferrari.

Australian parents are spending more than $297,600 raising a child to the age of 17 according to a new report out this week with a surprising finding that its not the toddlers or the teenagers costing us the most.

The Suncorp Bank Cost of Kids Report looked how much Australians spend on everyday expenses with a set of statistics sure to make the parent of any tween fall off their chair.

While you may have assumed that all those initial outlays for prams and cots and change tables and feeding chairs and nappies and special machines to blend up sweet potato to just the right consistency was the big hit when having kids unfortunately, you’ve assumed wrong.

If you, like me, have a child turning nine this year then read on because it’s these tweens who are making the biggest dent in our bank accounts.

The study found that the ‘tween’ years (9 to 11 years) have the biggest impact on a household budget – a walloping $1,630 per month.

Must be all those socks my son goes through.

Teenagers aged 15 to 17 are cheaper at $1,290 per month while infants and toddlers are the least expensive - infants costing families only $984 per month and toddlers $1,425 per month.

Suncorp Bank regional manager Monique Reynolds said it was commonly assumed that infants and teenagers required the most money.

“We have to rethink the way we budget,” she said.

“The research reveals tweens have emerged as the most expensive age group, which may come as a surprise to many parents as we tend to assume infants and teenagers require the largest financial investment,”

The research found that part of the increased costs may be our tweens love of screens with digital technology draining cash from household budgets at $59 a month.

60 per cent of tweens have non-school related electronic gadgets. We are also sending our tweens to greater and more expensive extra-curricular activities putting a strain on our wallets.

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The research found that food is the biggest monthly children’s expense - don't we know it when we look in the fridge with food costs peaking at $324 for 9-11 year olds a month.

Contrary to popular belief that the costs decreased with each subsequent children the report revealed the slightly depressing statistics that with each child comes greater costs.

“It appears the first-born is no longer the most expensive with the average expenditure per child actually increasing as the family expanded,” Ms Reynolds said.

“The average cost for a single child household was $1,118 per child, a two child household was $1,494 per child and a three plus child household was $1,787 per child.”

The report found on average Australian parents spend up to 27 per cent of their household income on their child per month.

A separate study last year found that while child-raising costs have gone up by 50% since 2007, our household incomes have only risen by about 25%.

With my oldest turning nine at the end of this year my only hope it to put him to work. He's got great skills if you have the need. He makes an excellent batch of Anzac biscuits, is a gun at putting out the garbage and, I’m told, is a champion at killing Zombies in Minecraft.

Any takers?