Holly Deane-Johns entering a south Bangkok courthouse.

Holly Deane-Johns entering a south Bangkok courthouse. Photo: Ron D'Raine

Convicted heroin trafficker Holly Deane-Johns has been released from Bandyup Prison in Perth, 12 years after she was arrested in Thailand, where she dodged the death penalty.

Media reports claimed Ms Deane-Johns, now aged 40, was seen leaving the facility early on Thursday and was met by two men whom she hugged, and was obviously overjoyed at her release.

Ms Deane-Johns, a West Australian, was 29 in 2000 when she was arrested in Thailand.

She and then 50-year-old Victorian, Robert Sydney Halliwell, had been monitored by narcotics agents for some time and were ultimately caught with 200 grams of heroin they were preparing to send to Australia via post.

While he was found with 180 grams of heroin, Ms Dean-Johns possessed 20 grams of the narcotic.

She initially faced the death penalty for the offence, but was sentenced to 31 years in jail, which was later reduced to 22 years and six months.

Ms Deane-Johns spent seven years in jail in Thailand before she was transferred to Bandyup, where she spent a further five years.

After expressing surprise at her sudden release, her lawyer Tom Percy, told Fairfax Radio that prisoners were usually only given 24 hours notice before being let free.

"Sometimes, it just happens very suddenly," he said.

The length of Ms Dean-Johns' incarceration was excessive, Mr Percy said.

"That whole case was just a monument to our obsession with drugs. She had so little drugs on her," he said.

"If she'd got 18 months here, I would have been astounded.

"She'd done massive time for what she did."

Mr Percy said the five years Ms Deane-Johns had to spend in the WA jail after she was let out of the Thai prison following a prisoner transfer request was "probably to appease the Thai authorities".

A bilateral agreement with Thailand, in place since September 2002, allows transfers of sentenced prisoners between the two countries.

When the transfer was approved in 2007, Ms Deane-Johns wanted to be closer to her boyfriend, fellow drug trafficker Stephen Wallace, who was doing time in Perth's Casuarina Prison.

A Seven News reporter who witnessed her release said Ms Deane-Johns, formerly a brunette, was now a blonde.