HONG KONG--The arrest in Thailand of a Canadian man suspected of having sex with young boys has focused international attention on a sordid industry that peddles children to pedophiles across Southeast Asia.

Grinding poverty, poor policing and no shortage of demand ensure that exploitation of children for sex thrives throughout the region.

Despite some high-profile prosecutions of child sex abusers, experts say lack of cooperation among governments is hindering efforts to keep children safe from pedophilia.

The Friday arrest of teacher Christopher Paul Neil, 32, was the culmination of an unprecedented appeal from Interpol for public help in finding him.

Neil is accused of sexually assaulting 12 boys and posting 200 pictures of the crimes on the Internet.

His case is the latest to draw attention to the fact that children are readily available in Southeast Asia for sexual predators who travel from the West for the sole purpose of having sex with minors.

Probably the highest profile offender is former rock star Gary Glitter -- real name Paul Francis Gadd -- now in a Vietnamese prison convicted of committing obscene acts with two girls, then aged 11 and 12.

Campaign groups say much of the demand for child sex is homegrown and accuse authorities of often turning a blind eye, or even colluding in the abuse.

Lack of public awareness is compounded by lack of data, and punishments are rarely harsh enough to act as a deterrent. Even those caught and sentenced can often have their punishments downgraded by paying off their victims and accusers, experts say.

"There is a lack of awareness in the general public, and there is a lack of awareness among certain government officials," said Alexander Kruger, a child protection specialist at UNICEF in Thailand.

In Indonesia, authorities do not see the children as victims but prosecute them as illegal sex workers, said Arist Merdeka Sirait, who heads the National Commission for Child Protection group.

Indonesia has had a national action plan in place since 2000, and an anti-human trafficking law was introduced in 2006.

But experts say that even where laws exist, implementation is often ineffective.

Sirait estimates that about 40,000-70,000 Indonesian children fall into the sex trade each year, two thirds of them trafficked abroad, while the group ECPAT, which campaigns against child prostitution, says Vietnamese children are being sent to Cambodia, China, Malaysia and Taiwan for abuse.

After decades as a haven for child sex tourists, Cambodia has been cracking down in recent years, arresting or deporting at least two dozen foreigners since 2003.

But the country's most notorious child sex market, a brothel village near Phnom Penh allegedly closed in 2004, still operates, albeit driven underground and more difficult to monitor.

Cambodians make up a large percentage of pedophiles, according to rights groups in the field, but domestic pedophilia is treated as an ordinary crime rather than a social problem.

"We don't deny that Asian men like to have sex with children here, but we have received very little information about this," said Major General Bit Kimhong, director of the Interior Ministry's Anti-Human Trafficking Department.

Australia and Japan, sources of child sex tourists, have dealt with the issue in vastly different ways.

In Japan, criticized as the world's main producer of underage pornography, the number of prosecutions involving child prostitution and pornography has risen in recent years -- peaking at 1,080 cases in the first half of last year.

But, said Keiko Saito, a Tokyo-based ECPAT official: "The government has done nothing to stop sex tourists from Japan."

One Japanese man was sentenced to prison after having sex with a 15-year-old Cambodian girl and posting pictures on his homepage last year but his sentence was suspended after he paid the girl compensation.

By contrast, Australia introduced laws in 1994 allowing Australians engaging in child sex overseas to be prosecuted at home, with individuals facing jail terms up to 17 years.

The Philippines has one of Asia's most widely-used anti-child prostitution laws which has led to the arrest and conviction of child molesters and pedophiles.

The most celebrated case in recent years was that of Filipino congressman Romeo Jalosjos, who was convicted in 1997 for raping an 11-year-old girl who was "sold" to him by her father.

Rights groups estimate there are around 1.5 million street children, of whom more than 30,000 have been prostituted, in many cases by their parents.

Rooted in poverty, as elsewhere, the problem was exacerbated in the 1980s by US bases in the northern cities of Clark and Subic, where bars employed children who ended up as sex workers for American soldiers.