Federal Privacy Commissioner Timothy Pilgrim has confirmed he will investigate how a file containing the personal details of asylum seekers was made available to the public through the immigration department's website.
The Guardian this morning revealed the security lapse by the department.
The Guardian article by Oliver Laughland, Paul Farrell and Asher Wolf reported that the "vast database" contained the "full names, nationalities, location, arrival date and boat arrival information" of asylum seekers.
The file contained the details of almost 10,000 people, including every asylum seeker imprisoned in on-shore detention centres and on Christmas Island, as well as those in community detention, the newspaper reported.
"This information was never intended to be in the public domain," an immigration department spokesperson said in a statement sent to Computerworld Australia.
"The department acknowledges that the file was vulnerable to unauthorised access. The file has been removed and the department is investigating how this occurred to ensure that it does not happen again."
"This is a serious incident and I will be conducting an investigation into how it occurred," a statement issued by the privacy commissioner read.
"As part of this investigation, the department has undertaken to provide me with a detailed report into the incident.
"Further, the [Office of the Australian Information Commissioner] will be working with the department to make sure they are fully aware of their privacy obligations and to ensure that incidents of this nature will not be repeated."
The Greens' immigration spokesperson, Senator Sarah Hanson-Young, said the privacy breach "makes a mockery of the Government's obsession with secrecy".
"Thousands of refugees have had their private details published online and the government must now take that into account when considering their claims for protection," the senator said in a statement.
"This is a very serious breach of privacy and yet another example of this government's failure to care for vulnerable people who are fleeing for their lives. The immigration minister must provide a full and frank explanation of how this breach occurred and what will be done to protect the people involved."