An unlicensed Cambodian doctor has been charged with murder for causing an HIV mass infection after he reused needles and syringes when treating patients.

It is believed at least 119 people, including children and the elderly, were infected as a result of the doctor's malpractice.

Hundreds of residents from the Roka village in the Battambang province, southern Cambodia, flocked to local clinics for testing since news of the mass infections was revealed earlier in December.

"He has confessed to sometimes reusing needles and syringes over the past years," said Battambang provincial police chief Sar Thet.

He added the 55-year-old self-styled doctor, identified as Yem Chroeum, was not believed to have undertaken any medical training and "had the intention to infect villagers with the HIV virus".

The motive behind the doctor's actions was unclear.

"He [Chroeum] was charged with three counts which include the intention to infect others with HIV/Aids, murder with cruel act and operating an unlicensed clinic," Prosecutor Nuon San said, AFP reported.

A woman who contracted HIV after being visited by Chroeum told Reuters: "After I gave birth to my child, I went to this doctor all the time.

"I suspect the virus may have been transmitted through injections or intravenously through a drip."

The first HIV case in Cambodia was reported in 1991. The virus has been contained though prevention and control efforts by the government.

As per UN estimates in 2012, there are at least 76,000 people living with HIV in Cambodia, which aims to reach a 0% infection rate by 2020.