In a post on Facebook this afternoon, Julie Wallace said her 21-year-old daughter's body had been found by police.
"Sara Zelenak is confirmed dead, they found her body & has DNA tests confirmed. Thank-you for all the overwhelming love & support from everyone," she wrote.
Prince Harry earlier joined those paying tribute to Ms Zelenak and Kirsty Boden.
At the launch of the 2018 Invictus Games at Sydney's Admiralty House today, the Prince began his speech by saying: "I'd like to start by sending my thoughts to those affected by Saturday's attack in London Bridge.
"Australians formed an important and vibrant part of the fabric of life in London, and we are reminded of that in good times and bad. Our hearts go out to the victims, their friends and families."
Sara Zelenak is believed to be the second Australian killed in the London attack.
South Australian nurse Ms Boden, who The Sun described as "The Angel of London Bridge" on a front page tribute, was last night named as the first Australian killed in the attack.
Ms Boden was killed after running to help others hurt in the attack.
"We continue to work with the United Kingdom authorities who have asked that we await official confirmation of the identities of the victims, and for the families to be officially notified, before we release their names," Ms Bishop said.
"The Australian Government has remained in close contact with the families who have requested privacy."
Prime Minister Malcolm Turnbull has spoken to the families of the two Australians.
"We are heartbroken by these terrible crimes and by this terrible loss," he said in an interview with 3AW today.
"This is heart-rending. This is the last thing that anybody expects to happen to their children in London."
Mr Turnbull would not confirm the identity of the second victim until the family had been formally advised by the British coroner.
Authorities believed all Australians caught up in the attack had now been accounted for, he said.
"Kirsty Boden was a young nurse who went to help victims of the attack and, tragically, has been killed by these cowardly, vicious terrorists," Mr Turnbull said.
"Sara Zelenak ... is a young Australian 21-year-old who was working in London, an au pair ... whose circumstances are being, have been the subject of very grave concern."
Mr Turnbull said that as a father himself, the conversation with both Kirsty Boden's and Sara Zelenak's families had been heartrending.
"We are facing a global threat," he said.
"This Islamist terrorism is a disease - it is corrupting, seeking to destroy from within the Islamic religion and of course lashing out to destroy and undermine our way of life.
"We are heartbroken by these terrible crimes and this terrible loss."
Sara Zelanak "absolutely beautiful".
BRISBANE woman Sara Zelenak - killed in the London Bridge terror attack - didn't drink and didn't do drugs. She was the smart, sensible girl next door who couldn't wait to meet her parents in Paris.
Speaking to media on Tuesday outside the family's home in Ormiston, east of Brisbane, Ms Zelenak's aunt Tara said she was an "absolutely beautiful" girl.
She described the former Moreton Bay College student as "absolutely beautiful", "the girl next door" and a "very special kindred spirit".
"She's one of those people that doesn't drink, doesn't do drugs, doesn't do anything wrong.
"She's amazing and she's 21 years of age."
Ms Zelenak was working in London as an au pair, and was due to work on Saturday night but had a change of plans after the grandparents of her young charges took over instead.
She was leaving the bar London Grind, near the bridge, with her friend Pri Gonçalves when they heard the van crash and saw people running from the carnage.
The friends were separated as people ran for their lives from a white van ploughing into pedestrians on London Bridge.
Ms Zelenak's mother Julie Wallace was told earlier this week how her daughter had narrowly missed being caught up in the two previous terror attacks in the UK in the past three months - a similar attack at Westminster where four pedestrians and a policeman were killed and the suicide bombing at a Manchester pop concert which killed 22 people.
"Where (the) policemen were stabbed three months ago, she was there the day before in the exact same spot," Ms Wallace told 97.3FM radio in Brisbane.
"The one with Ariana Grande (in Manchester), she was going to go to the concert."
Ms Wallace said she had spoken to her daughter on Friday afternoon, who had been excited about an upcoming trip where she would join her in Paris.
"She said, 'Oh mum! It's only 28 days until you and I and dad can have baguettes and cheese and croissants in Paris. I'm so excited to go to Paris!' because she hasn't been.''
"She's a very smart, sensible girl, she is healthy, fit, trim, taut, terrific - she doesn't do anything wrong in any way.
"She's very sensible, far more sensible than I was at her age."
Ms Wallace told 97.3FM she felt "absolute terror'' when she heard about the attack.
She said Ms Zelenak had been travelling since March, having a "wonderful trip'' and life experiences, and she was counting down the days until she travelled to Europe to meet her daughter to continue the holiday.
"But horror, absolute horror,'' she said.
South Australian nurse Kirsty Boden was confirmed dead by UK authorities overnight.
Two other Australians are recovering after being stabbed in the neck by the terrorists.
Candice Hedge, 31, of Queensland, is recovering in hospital after being attacked in Elliott's cafe. Andrew Morrison, of Darwin, is home in Australia after being stabbed in the throat as he walked down the street.