The US is in the process of implementing new legislation that experts and officials say could help Cambodia protect its children from foreign-born pedophiles, a need whose urgency was highlighted most recently by the case of Robert Boehnlein, a convicted US sex offender arrested in Battambang for allegedly raping a 5-year-old.

While Cambodia has long been a destination for American child sex tourists, the International Megan’s Law, signed by former US President Barack Obama in February 2016, requires any American with a child sex conviction to get a stamp in their passport, which would tip off immigration authorities in foreign countries of their history of sexual abuse.

A US State Department official said the passport identifier provision will not be applied until the process is approved by the secretary of state, the secretary of homeland security and the attorney general.

The law has been protested by sex offender rights groups, who have said the stamp amounts to a “scarlet letter” of discrimination against anyone with an offence on their record. But the law has been welcomed by authorities and child protection groups in Cambodia.

Sok Veasna, a director at the Interior Ministry’s General Immigration Department, said immigration authorities do not currently have the means to conduct background checks on foreigners trying to enter the country. Although he had never heard of the US law, he said such a measure would be “very good for our country”.

“We let convicted child offenders into our country just because we don’t know,” Veasna said.

“But if we know the person committed a crime, we will not let him into our country. We can protect our people.”

The American law also streamlines the process of monitoring convicted child sex offenders who are overseas and communicating with foreign governments about cases involving American nationals.

Child Protection Unit Director James McCabe said he was pleased that the law would ostensibly stop someone like Boehnlein, 65, from entering Cambodia in the future, but said countries should look at going even further.

One such measure is currently being implemented by Australia, which passed a law in June that will nullify the passports of Australian registered sex offenders upon request from a “competent authority”.

Convicted Australians currently living abroad will be given a one-way “alternative travel document” so they can return to Australia, according to a spokesperson from Australia’s Department of Foreign Affairs and Trade.

McCabe allowed – as some critics of the US law have charged – that some punishments needed to be reassessed for being too harsh, for example in cases involving underage teenagers exchanging nude photos and other lower-level offences. But he encouraged Western governments to do more to protect children outside their borders.

“Countries have a duty to protect not only their own citizens but all citizens from sexual predators,” he said. “I’d encourage all major countries to examine Australia’s travel ban on sex offenders and consider it.”

A spokesperson from the Australian Ministry for Foreign Affairs said that the new law will go into effect by December.

The US State Department did not give a timeline for the law’s full implementation, but had it been in force at the time of Boehnlein’s entry into Cambodia about two years ago, immigration officials would have been notified of his prior conviction in 2002 for sexually abusing his daughter in the US.

Boehnlein was sent to pretrial detention in Battambang last week for allegedly raping the daughter of his Cambodian wife on multiple occasions.

“I think she [the mother] did not file a complaint or report it to the police because she was financially supported by him,” said Born Vannara, chief of the provincial police’s anti-human trafficking unit, adding that Boehnlein was giving the family roughly $600 per month.

The charges of rape with aggravating circumstances carry a sentence of seven to 15 years in prison if convicted.