AUSTRALIANS are the biggest exploiters of Thailand's child sex industry, according to a study by Johns Hopkins University.

Australians make up the largest portion of foreign sex offenders against children in Thailand, according to the research that studied patterns of arrests and prosecutions between 1995 and 2006.

Our cash fuels the US$31.6 billion industry in child sex trafficking, which sees 1.8 million children as young as eight years old being sold for sex - sometimes up to ten times a day - until they're considered "worthless" before they reach their 30th birthday.

It is an industry a global network of advocate groups concludes is a "massive human rights violation that is currently going largely unnoticed around the world".

Bernadette McMenamin, CEO of Child Wise Australia, says child sex trafficking remains a hidden problem that most Australians have become complacent about - even though a main root of the global crime is the Australian offender.

"People tell us, 'It happens overseas. Isn't that an issue we talked about years ago?' But what we've found is that ... the supply and demand factors fuelling child sex slavery have actually grown," she said.

"The number of children entering the trade has grown. Efforts to combat this problem have not succeeded despite pouring money into overseas governments."

A new global campaign called "Stop Sex Trafficking of Children and Young People," will be launched today to help reverse the trend and bring the issue back into the homes of the average Australian.

Being run across 45 countries, the campaign aims to raise awareness, conduct a survey on people's attitudes and lobby national governments to intervene on behalf of exploited children.

In February, Child Wise will step up the campaign by backing stalled amendments to child sex tourism laws in the federal parliament.

Rather than seeing authorities wait for child sex to occur before acting, the amendments seek out preparatory offences, aiming to stop sex offenders from travelling overseas, buying flights and possessing child pornography.

"We've waited long enough," Ms McMenamin says of the proposed changes. "We're simply not keeping up with travelling sex offenders."

Only small changes are required to save Asian girls from being sold into a life of slavery, she says.

The Body Shop has already joined the Child Wise campaign by selling a hand cream that directs profits to Cambodian outreach programs. Such programs can provide support for girls and keep them in school with books, pens and bicycles.

It may not seem like a lot but the average child sex slave is sold for only a few hundred dollars by a family or boyfriend in poverty desperate for cash, she says.

In Cambodia children are brought in from Vietnam or taken from village to village, then off to Thailand.

All these victims suffer lifelong mental and physical damage. Some contract HIV/AIDS while most find it hard to reintegrate into society after a decade of such slavery.

Ms McMenamin says most Australians view the price of petrol as a greater concern than the welfare of foreign children.

"We have increased awareness and there have been some arrests but overall we're not putting a dent in the problem," she says.