In Wollongong Local Court, Magistrate Geraldine Beattie told Joel Bill he would remain behind bars until his non-parole period of 16 months was completed after he confessed to sending a death threat to the woman while he was in custody on an unrelated charge.

The letter, part of which read "...even more of a reason for me to jump all over his f--king head. He is gonna cop it all...I'm gonna kill both you f--king lifes (sic)" was delivered to the woman's home on December 31.

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Bill walked free from jail on February 18 after completing his sentence on the unrelated charges, however was locked up again two days later after Magistrate Jillian Kiely granted a police application to have him returned to prison.

During the court proceedings in February, Magistrate Kiely said the case of the Baxter family in Queensland, which police suspect was a shocking act of domestic violence perpetrated by the children's father against his kids and wife Hannah, was a timely reminder of the potential dire consequences of family violence.

"The timing of this matter couldn't be worse given what was in the news about the mother and her three children who were killed at the hand of an ex-partner and father," Magistrate Kiely said.

"The court takes death threats very seriously."

In court last week, lawyer Lemar Miakhel said Bill was remorseful for his actions and submitted his client should be granted an intensive correction order, which would be served in the community.

"Magistrate Kiely made significant reference to the death of Hannah Baxter," Mr Miakhel said.

"After talking to my client about the Baxter deaths and the gravity of his actions, he now understands how seriously the court takes domestic violence offences.

"He regrets his behaviour.

"He was not in a good headspace and was not thinking straight when he wrote the letter, but knows that is not an excuse."

Bill read out a letter of apology saying he "found out she was with another partner and pregnant to him," and was "very regretful" and "sorry for my immature actions".

Magistrate Beattie, in handing down her sentence, said "no one should have to receive a letter like that."

"It is pretty clear what you wanted to do when you got out," she said.

"It is pretty clear how you wanted to make her feel.

"You knew the affect the letter would have on her. Clearly you intended to terrify her.

"Whether or not she has a new partner, or 10 partners or is pregnant, that is none of your business."

Magistrate Beattie said Bill's lengthy domestic violence history towards his former partner included custodial sentences, breaches in AVOs, intimidation and assault offences.

"Your criminal history does not assist you and you committed an offence while serving a sentence in custody," she said.

Magistrate Beattie said she did not feel any sentence served in the community would protect the victim but did take into account Bill's plea of guilty and remorse.

Bill will be eligible for release in June next year.