Holly Deane-Johns, 32, from Perth, was sentenced to 12 years in jail for heroin possession and 19 years for smuggling, the terms to be served consecutively in Thailand's Bangkhen women's prison.

She had pleaded guilty to the crimes, which in Thailand are punishable by death.

Her co-accused, 57-year-old Robert Halliwell, from Victoria, was jailed for life after pleading not guilty to the charges.

They were arrested in September 2000 and accused of trying to mail several grams of pure heroin to Australia.

Authorities later found another 110 grams of heroin in Halliwell's apartment, and 35 grams in Deane-Johns' home.

Halliwell had lived in Thailand for several years at the time of his arrest while Deane-Johns had gone to Bangkok a few months before her arrest.

Halliwell has not yet indicated if he will appeal his sentence. Deane-Johns will not appeal.

A close friend of Deane-Johns, 69-year-old Perth Buddhist Brian Haffenden, said her term was the best possible outcome because it may allow her to return to Australia within years to serve out her time.

"She's elated, she's very happy. She gave me a great big smile and put her thumbs up when the sentence was passed. And I got a great big hug as well," Mr Haffenden told AAP from Bangkok.

"She qualifies for repatriation under the prisoner exchange between Thailand and Australia, therefore we would anticipate positively that within four years she could be back in Australia."

Mr Haffenden based his remarks on the repatriation of fellow Perth resident John Doran, who in April became the first Australian prisoner allowed to serve out his sentence in his home country.

Doran was serving a 10-year jail term in Thailand for a $US1,000 ($A1,630) travellers cheque fraud. He had already spent more than five years in a Thai jail.

Mr Haffenden said Deane-Johns had spent two years, 10 months and four days in jail in Thailand, and said she could be returned to Australia provided she showed good behaviour.

Deane-Johns' brother Mark, from Adelaide, and sister Amy, from Perth, also were in court in Bangkok.

Mr Haffenden said Deane-Johns had been a manipulative person when he first met her following her conviction, but had turned her life around since he had known her.

"She's no longer interested in drugs in any way shape or form and she wants to become a people helper when she eventually gets out of prison," he said.