Major banking institutions say they are intercepting hundreds of thousands of abusive messages sent through transfer descriptions in a lesser known form of domestic violence.
Commonwealth Bank (CBA) said it blocks 400,000 "insidious" transactions with offensive language by about 1,500 perpetrators annually with automatic filters and manual reviewing.
National Australia Bank (NAB) said it blocked 15,000 similar abusive messages a month, suspending or denying products to those sending them.
Perpetrators use the transaction description on online banking platforms to send threatening messages in low-value payments to former or current partners.
"Usually the transactions are about 1 cent, and the sole purpose is to deliver a message to the receiver ... where the victim-survivor may have blocked that person from every other communication channel," head of customer vulnerability at CBA Caroline Wall said.
Ms Wall said concerns included messages like "I know your new address" or "if you don't unblock me I'm going to show up to your house".
Genuine payments like child support or property repayments are also used to send abusive language, she said.
Domestic violence support service Full Stop Australia's client and clinical services director Tara Hunter said bank transaction messages were a last resort through "any means necessary" for perpetrators.
"When we're talking about the abuse that happens in transactional issues, there's ongoing intimidation, abuse, and psychological fears," she said.
"This is about them indicating that they're still present. 'I'm still here, I still have control over you' ... so it's a subtle but very intimidating reminder."
Australian-first pilot works towards police referrals
CBA in September launched a police referral pilot in NSW that made it easier for customers to report technology-facilitated abuse to law enforcement.
It is the first of its kind in the country, and just over six months on, a number of cases have met the threshold for reporting.
The ongoing partnership allows a streamlined process to escalate these transactions with the permission of the victim-survivor, with a 24-hour cooling-off period in case they change their mind.
"Under this pilot, the CBA has the authority to be able to report repeated incidents of abusive transactions directly to a specialist unit ... so they can investigate the issue and determine whether or not to take action," Ms Wall said.
"Until now, victim-survivors of this form of abuse had to collect their own evidence and then take that directly to their local police station.
"But now we pull together the evidence on behalf of that customer with their consent and provide that directly to the NSW Police force so they can commence and investigation straight away."
Last month, a federal inquiry was announced to assess how financial institutions can better identify and prevent instances of abuse on their platforms.
NAB chief executive Andrew Irvine acknowledged more needed to be done to stamp out financial abuse more broadly.
"Where it's abuse or victimisation or even violence, we having training and data and analytics that help us," he told ABC News Radio this month.
"This is something that's sometimes hard to detect ... This is tough and I think it's incumbent on all of us to be doing more here."
Perpetrators will 'take absolutely every single measure'
Ms Hunter said banks stepping up to address financial abuse was a positive development in a growing area of concern.
"I think that it's very consistent and telling of the number of people impacted by economic abuse in our society."
The Australian Bureau of Statistics' Personal Safety Survey found that 1.6 million women had experienced a form of economic abuse, including interference with bank accounts or accumulated debt on shared accounts.
Full Stop Australia also sees the withholding of income and welfare payments, or the controlling of spending in joint accounts as common examples of detrimental financial abuse.
"There's lots of ramifications, one is the ongoing impact for people to be able to make their day-to-day living expenses," Ms Hunter said.
"It's also part of coercive control, where if women don't have access to financial means or they don't have access to expenses, then if they are wanting to leave then it makes it incredibly difficult."
As more efforts are made by the banking industry, Ms Hunter said it was vital that safety measures were put in place.
"We need to make sure there's appropriate training for bank staff because they haven't chosen to be a frontline social worker," she said.
She would also like to see banks ensure they are not increasing risk to their clients.
"A lot of women are being tracked by their partners either through phone or email, so there needs to be some really clear strategies in place to know women are in a safe space to take a call or to receive a text [from their banking institution].
"As these kinds of examples demonstrate, if you've got someone who want to control you, they will take absolutely every single measure."