The number of “threat to kill or injure” offences has almost tripled in the past decade, making it one of the fastest-growing crimes in the state.

Offenders are increasingly using social media and text messages to convey threats, but in the most disturbing cases, some estranged fathers have instructed children to pass on death threats to their mothers.

Victoria’s Women’s Domestic Violence Crisis Service chief executive Ann- ette Gillespie said it was increasingly common for threats to continue despite the enforcement of family violence intervention orders.

“Threats are a key weapon in the grooming process of perpetrators of violence against victims that can start in the very early stages of the relationship and can escalate over time to threats to kill — either themselves, the woman or family members,” Ms Gillespie said.

“The ultimate threat is to kill the children.”

She said police were better equipped to identify family violence and whether victims were at risk.

“We’re asking the question ‘Have there been threats?’ Automatically now, police are doing the same,” Ms Gillespie said.

Victoria Police crime statistics show 1559 threats to injure and 4893 threats to kill were reported in 2012-13.

The figures exclude threats directed at police officers and public officials.

Head of Victoria Police’s family violence unit Detective Superintendent Rod Jouning confirmed most reported threats related to domestic violence.

Most threats were made by men.

But Detective Supt Jouning attributed the sharp rise in the past 10 years to changes in police reporting of domestic violence offences, rather than any significant rise in violence.

While improved reporting helps explain the surge in death threats, the number of cases that proceed to court remains significantly lower.

Many victims are intimidated and psychologically scarred by the abuse and unable to testify against violent partners, according to Helen Matthews, the principal lawyer at the Women’s Legal Service Victoria.

“Some of our most vulnerable clients are suffering from post-traumatic stress disorder, which can obviously affect their ability to give evidence in court,” Ms Matthews said.

Between 2010 and 2012, about a third of reported death threats went to court, with just 23 per cent of men found guilty of the offence receiving a custodial sentence in the Magistrates Courts, according to the Sentencing Advisory Council.

During that time, 2241 men were found guilty of “threat to kill” offences in the Magistrates Court, while 217 women were convicted of the same offence.