Australia’s Foreign Minister, Stephen Smith, is a man who takes the nostrum ''in foreign affairs words are bullets'' very seriously indeed.

So when Smith used words like ''sorrow'' and ''regrettable'' when he announced today that the Australian Government would expel an Israeli diplomat over the Dubai fake passport affair, it was a sign that the relationship between the two countries has been seriously damaged by the incident.

In a press conference today Smith disclosed the findings of investigations by Australian police and intelligence agencies into the use of four Australian passports in an operation to assassinate a Hamas commander in Dubai in January.

He said the investigation had reached three conclusions.

Firstly, there was absolutely no evidence that any of the four Australian passport holders had been anything other than victims of deliberate passport fraud.

Secondly, the nature of the counterfeiting and cloning of the passports was so sophisticated that it could only have been effected by a nation state through its intelligence services.

Thirdly, the evidence established ''beyond doubt'' that Israel was responsible.

''Regrettably this is not the first occasion on which Australian passports have been misused by Israel,'' he told the press conference.

''Regrettably what occurred in this Dubai incident is contrary and in breach of understandings reached between Australia and Israel of some years standing.''

Smith received the final results of the investigation last week.

He took a recommendation to cabinet's national security committee this morning to retaliate by expelling an Israeli diplomat from Tel Aviv's embassy in Canberra within the week.

''The decision was made much more in sorrow than in anger,'' he said.

''Australia and Israel are firm friends and that remains the case but this was not the act of a friend.''