Two Australians, a man and a woman, were injured in the attack in Russell Square, but their injuries were not life threatening.
The man has already been discharged from hospital and a woman is expected to be discharged soon, a spokesperson for the Australian Department of Foreign Affairs and Trade (DFAT) said.
Another Australian woman was at the scene of the attack but was not injured, the spokesperson said.
"Consular assistance has been provided to the man and one of the women and DFAT is attempting to contact the other woman involved to offer consular assistance," the DFAT spokesperson said.
Members of the public and businesses have left floral tributes at the scene of the attack, where an American woman was killed.
Darlene Horton, 64, was the wife of a university professor from Florida who was hours away from flying home when she was attacked.
The 19-year-old was Tasered by armed police before being arrested on suspicion of murdering a woman and injuring five others.
Police have ruled out terrorism as a motive for the stabbing attack in London's Russell Square.