The Australian Government says the police and the ASIO intelligence agency have launched a full investigation into the apparent misuse of Australian passports in the assassination of a Palestinian militant in Dubai.
Three people who used forged Australian passports have been named among 26 suspects in the killing of Hamas official Mahmoud al-Mabhouh last month.
Mr Mabhouh was found dead in a Dubai hotel room on 20 January.
A post-mortem report said he had been electrocuted and then suffocated.
The authorities in Dubai say it's almost certain that the Israeli intelligence agency Mossad was responsible, but Israel has repeatedly refused to confirm or deny involvement.
Australia's Foreign Affairs Minister, Stephen Smith, says he called the Israeli ambassador on Thursday morning to express his deep concern over the issue.
He says he told the ambassador it would not be seen as the act of a friend if Israel turned out to be involved in the abuse of Australian passports.
Prime Minister Kevin Rudd says that any state complicit in the use or abuse of the Australian passport system is treating Australia with contempt, and that there will therefore be action by the Australian government in response. Mr Rudd did not elaborate on the nature of that action.