CANBERRA, June 7 (Xinhua) -- Two of the victims of the London terror attack which occurred at the weekend were Australian, the federal government confirmed on Wednesday.

Foreign Minister Julie Bishop confirmed the news through a statement on Wednesday morning, saying that that Australian authorities were working closely with British counterparts to confirm the identities of the Australians killed when three terrorists drove a van into pedestrians on the London Bridge, before exiting the vehicle and stabbing those at nearby venues.

"The Australian government is deeply saddened to confirm that two Australians have been killed in the London terrorist attack," Bishop said.

"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.

"The Australian government has remained in close contact with the families who have requested privacy."

While the government did not publish the names of the two victims, the family of 28-year-old South Australian woman Kirsty Boden confirmed her death in a statement, saying the career nurse "ran towards danger" - doing what any emergency services member would do before she was killed.

"She was the most outgoing, kind and generous person who loved to help people," Boden's family said.

"Helping people was what she loved to do in her job as a nurse and in her daily life. As she ran towards danger, in an effort to help people on the bridge, Kirsty sadly lost her life.

"We are so proud of Kirsty's brave actions which demonstrate how selfless, caring and heroic she was, not only on that night, but throughout all of her life. Kirsty - we love you and we will miss you dearly."

Fears are also being held for the fate of missing Queensland au pair, 21-year-old Sara Zelenak, but it remains unclear whether she is the second Australian victim.

Speaking on local radio on Wednesday morning, Prime Minister Malcolm Turnbull said the federal and state governments were in contact with the families of both Boden and the missing Zelenak, but could not confirm whether the latter was the second Australian fatality.

"We have been in touch with the families of the two young women, Kirsty Boden and Sara Zelenak," Turnbull told Macquarie Radio.

"We have been very assiduous in working with the families and taking care to respect their privacy. British authorities - the coroner - have not yet formally advised of the deaths of either of those young women and their families are either in the UK now or on their way there."

The prime minister described the heartbreaking loss as "tragic" and said that he couldn't imagine the pain felt by the families.

"I'm a father of a certain age, and those girls could be one of my kids. This is heart-wrenching, this is the last thing that anyone expects to happen to their children when they are in London," Turnbull said.

Turnbull added that violent extremism was a "disease" in modern society - but one which Australian authorities remained equipped to deal with, after he yesterday confirmed the nation's terror threat level would remain at "probable" in the wake of the latest attack.