More than 4,000 inmates at Prey Sar prison have been tested for drugs in the week since testing began in what will soon be a nationwide effort, with 23 testing positive for methamphetamine, according to prisons officials.

The universal testing initiative comes amid a national war on drugs launched on January 1, and after the exposure last year of drug dealing networks operating out of prisons, and the establishment of a committee tasked with investigating drug trafficking on the inside.

Nouth Savna, spokesman and deputy director-general for the Ministry of Interior’s General Department of Prisons, said the testing was part of the push to “combat drugs across the country”, adding that the testing is still ongoing.

Meas Vyrith, secretary-general of the National Authority for Combating Drugs, said inmates at Prey Sar began getting tested last Monday, and that all inmates in the country will eventually be tested with a rapid-result urine test.

Savna said officials were still working to determine where the 23 inmates got their meth but said there are three ways that drugs can land in prisons: visitors, which he characterised as the most popular means of trafficking; throwing substances over the prisons’ fences; and prison guards smuggling them in. “Various stakeholders will convene to discuss how to go about designing a solution” for treatment and prevention of drug use among inmates, he said.

Vyrith maintained the inmates who tested positive for meth got the drugs from relatives who came to visit them.

“We are going to discuss with the General Department of Prisons on strictly controlling all the things [brought by visitors] before allowing people to bring them in or hand them over to inmates” he said.

On Friday, the General Department of Prisons issued new guidelines for finding and reporting contraband for prisons nationwide, Savna said. “[They] were very urgently made,” he said.

Since last year’s commitment to crack down on drug networks inside and outside of the country’s prisons, Savna said only a couple such networks have been discovered, and have been small in scale. “They are not systematic,” he said, though the committee tasked with investigating hasn’t issued a full report.

Yesterday, a taskforce at a prison in Kampong Thom found four mobile phones, which could be used to coordinate drug deliveries, he said. On Sunday, a guard found an unspecified amount of drugs buried in the ground in Correctional Centre 4 in Pursat, but “nobody came forward”, he added.

Just a couple of days ago, a woman visiting a prisoner in Kratie was caught trying to smuggle a “substantial” amount of meth in packets hidden inside a milk carton.

David Harding, an independent drug expert with years of experience working in Cambodia, said he wasn’t surprised to hear about the prevalence of drugs in the prison system, especially with the “massively overcrowded prisons” where officials often need to “beef up security”.

However, he said, the issue is not unique to Cambodia. “You find a culture of drugs in prisons across the globe,” he said, adding that Cambodia needed to start drug users into treatment rather than prisons.