Australian authorities had already warned Israeli intelligence against using doctored passports in its clandestine activities around the world, the Australian newspaper The Australian reported on Thursday.

The Australian report came as Canberra warned Israel earlier Thursday that if it was involved in the alleged use of three forged Australian passports in the assassination of a Hamas leader in Dubai, it would not be considered the act of a friend.

The Canberra government called in Israel's ambassador after three people holding Australian passports were listed on Wednesday among 15 new suspects in the assassination of Mahmoud al-Mabhouh. Dubai authorities are investigating the use of at least 26 possibly fake passports in connection with the killing.

According to sources quoted in the article, Australian authorities approached Israel in the 1990s to seek assurances that Australian passports would not be used in Mossad activities after it was feared Israeli agents had doctored New Zealand passports.

During that meeting, the article claims, the Israelis said they condoned such identity theft, with Australian participants describing their response as "enraged self-righteousness."

The Australian foreign minister at the time, Alexander Downer, confirmed to The Australian that the then Canberra government warned Israel in at least one occasion not to issue fake Australian passports to its intelligence operatives.

"I'm not 100 per cent sure that I didn't myself raise it with the Israelis," Mr Downer told The Australian.

Downer added that the warning was issued in the context of a series of botched operations involving Mossad agents travelling on fake passports. "My recollection is that over time we have raised this issue with the Israelis," he said.

"We have raised the issue of Israeli intelligence officers using foreign passports and that they should not consider using Australian passports."

Dubai police have said they were almost certain that members of Israel's Mossad spy agency killed Mabhouh in his hotel room in January. The emirate Wednesday identified 15 new suspects in the assassination; Haaretz has learned that 10 of them share the names of Israelis who hold dual citizenship.

A list of 11 people suspected in the assassination released last week by Dubai also included the names of six British-born Israelis, whose names appeared on forged British passports thought to have been used by the killers.

Australia's Foreign Minister Stephen Smith said investigations were still under way, but the three Australians were also apparently innocent victims of identity theft.

"I made it crystal clear to the ambassador that if the results of that investigation cause us to come to the conclusion that the abuse of Australian passports was in any way sponsored or condoned by Israeli officials, then Australia would not regard that as an act of a friend," Smith said.

In an interview with Australian radio, Australian Prime Minister Kevin Rudd also emphasized the severity of the situation. "We will not be silent on this matter. It is a matter of deep concern. It really goes to the integrity and fabric of the use of state documents, which passports are, for other purposes," Rudd told Australian radio.

"Any state that has been complicit in use or abuse of the Australian passport system, let alone for the conduct of an assassination, is treating Australia with contempt and there will therefore be action by the Australian government in response," said Rudd.

The three using Australian passports have been identified as Daniel Bruce, Nicole Sandra McCabe and Adam Korman. The other new suspects also include Daniel Marc Schnur, Gabriella Barney, Roy Allan Cannon, Stephen Keith Drake, Mark Sklur and Philip Carr, traveling on British passports; Ivy Brinton, Anna Shauna Clasby and Chester Halvey, on Irish passports; and David Bernard LaPierre, Melenie Heard and Eric Rassineux, on French passports.

The suspected killers' use of passports from countries including Britain and France has drawn criticism from the European Union that diplomats said was aimed at Israel. Some of the countries involved have summoned the Israeli ambassadors.

"Friendly nations who have been assisting in this investigation have indicated to the police in Dubai that the passports were issued in an illegal and fraudulent manner," the Dubai government said.

The French AFP news agency quoted French officials on Thursday saying that the suspected killers of Hamas strongman Mahmud al-Mabhuh last month in Dubai used forged French passports, effectively stealing the identity of French citizens.

Foreign Ministry spokesman Bernard Valero told reporters that the documents were "clearly forged," allowing the "impersonation of French citizens."

The three passports referred to were among the fifteen new ones announced Wednesday by Dubai police, who have claimed they were nearly certain that members of Israel's Mossad spy agency killed Mabhouh in his hotel room in January.

"Three passports mentioned in this announcement by the Emirates appear to be clearly forged and there was impersonation of French citizens," Valero told AFP.

Besides the three French passports, Dubai police claimed to have found six British passports, as well as the three French allegedly forged, three Irish and three from Australia.

Also on Thursday, Irish Foreign Minister Michael Martin during a visit to the Gaza Strip said that no Irish citizens were among the assassins of the Hamas commander.

Martin, paying his first ever visit to the blockaded enclave of the Gaza Strip, told a news conference at UNRWA headquarters in Gaza City "the assassins of al-Mabhouh were not Irish."

"They are people who forged passports that belong to Irish citizens," Martin told reporters about the assassins. He said the investigation would "continue in this serious issue until the truth is revealed."

"I don't think that there is one single Irish citizen is involved in the case," said Martin, who crossed into the Gaza Strip earlier on Thursday through Rafah crossing on the borders between the enclave and Egypt.

Israel has not denied or confirmed it played any role but Foreign Minister Avigdor Lieberman said there was nothing to link it to the killing. The United States, Israel's main ally, has kept silent about the affair.