The mother of an Australian man linked to the assassination of a militant leader in Dubai says the photo in the passport used to name him as a suspect is not his.

Joshua Daniel Bruce is one of three Australians named among 15 suspects in the killing of senior Hamas figure Mahmud al-Mabhuh in Dubai last month.

Foreign Minister Stephen Smith said it was believed Mr Bruce, Adam Korman and Nicole McCabe, all Victorians who live in Israel, were not involved in the murder.

"Preliminary analysis by the Australian Federal Police (AFP) together with the Australian Passport Office shows that the three Australian passports appear to have been duplicated or altered," he said.

"At this stage Australian officials have no information to suggest the three Australian passport holders were involved in any way other than as victims of passport or identity fraud."

Mr Bruce's mother, Sarah Bruce, fears her son, who lives in Jerusalem, may be the subject of reprisal attacks, but she hopes people realise he has been the victim of identity theft.

"I am fearful, but hopefully everyone will see that it is fraud," she said from Melbourne.

"It's not his photo in the pictures they're flashing around everywhere."

She also said it was not his date of birth or signature in the Australian passport.

Ms Bruce said she was "totally shocked" when the Federal Government rang her early this morning to tell her that her son had been linked to the murder.

"Never, never, he's not that type," she said.

She said she had spoken briefly to Mr Bruce, who had no idea he had been implicated.

"He was unaware of everything that was going on," she said, adding that her son had lived for seven years in Jerusalem, where he was studying Judaism.

Bilateral relationship under pressure

Mr Smith has warned Israel that its relationship with Australia could be damaged if evidence is found it was involved in forging Australian passports.

Dubai police say the killing was almost certainly an Israeli hit.

Israel's ambassador to Australia Yuval Rotem was summoned to Parliament House in Canberra for a brief meeting with Mr Smith.

"I've 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 the act of a friend," Mr Smith said.

Mr Smith said he expected a response from Israel but did not know when that might be.

The Israeli foreign minister has said there is no proof his country carried out the killing.

Prime Minister Kevin Rudd has vowed the Government will "get to the bottom" of the case.

Australian passport officials have been in touch with the three Australians.

Passports become political

Meanwhile, Opposition Leader Tony Abbott says he wants to know why the Government has not ensured that Australia's passport system is more secure.

But Mr Smith says Mr Abbott should not seek to score political points over the matter because the passports in question were issued in 2003.

"Last time I looked, in 2003 you were a minister in a previous government," Mr Smith told Mr Abbott.

"You were ... a member of the executive which oversaw the issuing of that passport.

"You should think very carefully before you speak on these matters."

- ABC/AAP