Natti Jitsawang, the head of the Thai prisons department, said he would inform the justice ministry to start the parole process, which could take up to two months.
"The committee will ... consider her behaviour in prison," he told the AFP new agency.
"We plan to take her on as a trainer at the prison if she gets out."
Siriporn, though, seemed to have other ideas. "When I'm free I'll carry on fighting," she said after the match. "I want to fight all over the world."
During the fight Siriporn was cheered on by hundreds of supporters as she entered the makeshift arena accompanied by two women dressed as traditional Thai warriors.
"Now she has the chance to be free and fight around the world"
head of Thai prisons department
The ring girls who carried the signs announcing each round were transvestites serving time at the jail.
They wore high heels and strutted around the ring as a prison band played folk music.
Siriporn was on the attack from the start and repeatedly forced Miyano on to the ropes with a barrage of punches.
The intense afternoon heat took its toll on her Japanese opponent, who twice fell to the canvas as a result of Siriporn's relentless attacks.
To defend her title, Siriporn will next meet the winner of a fight between Mexico's Delia Lopez and Julia Sahin from Germany.
|The fight took place at Thailand's notorious |
"Bangkok Hilton" prison [Reuters]
"After we know who is the winner, we will organise the time and place for the bout against Siriporn," a WBC co-ordinator said.
"But normally Siriporn would have to fight within six months."
Immediately after the fight, Natti Jitsawang, the head of the prisons department, said Siriporn's criminal days were over.
"We will start the process for her parole immediately. We gave her a chance to show us her talent, and she has done that.
"She is a changed woman, and now she has the chance to be free and fight around the world."
He said he expected her to be freed within as little as two months.