Immigration officials are faced with a sharp rise in numbers seeking Australian residence through sham marriages.
The Immigration Department in 2004-05 received 1,909 allegations of contrived marriages and relationships - a rise of 22.4 per cent on 2003-04.
The annual summary of border compliance statistics also shows that in the same period, the department finalised the handling of 1,796 allegations of contrived marriages, a 19 per cent increase.
Of the 1,796 matters finalised, 1,145 were dealt with through administrative action and 15 briefs of evidence were submitted to the Commonwealth Director of Public Prosecutions (DPP).
So far, six of those submitted to the DPP have resulted in convictions.
Department of Immigration and Multicultural and Indigenous Affairs (DIMIA) statistics show allegations of contrived marriages have risen substantially since 2000-01, with the vast majority occurring in NSW and Victoria. DIMIA said the main aim of such arrangements was to gain Australian residence.
It said such activities endangered the immigration program by allowing in otherwise ineligible individuals and by creating a perception that contrived marriages were a convenient gateway to settlement in Australia.
"Organised contrived marriages and relationships are a high priority for DIMIA investigation activity and persons convicted can face penalties of up to 10 years imprisonment and a fine of up to $100,000," the department says in its report.
The report reveals an increase in all types of immigration document fraud over the past five years.
On the plus side, instances of document fraud detected at Australian airports have dwindled substantially from a peak of more than 300 cases in 2000-01 to around 100 in 2004-05.
That is visa and passport fraud, in which the most common technique is photograph substitution.
The report also confirms the rising problem of Indonesians illegally fishing in northern waters.
In 2004-05, a total of 1,485 illegal fishermen were apprehended - a 62 per cent increase on the 937 in 2003-04. A total of 1,417 illegal fishermen were sent home and their vessels and catch were confiscated.
"The increase in apprehensions can be attributed to strong inter-departmental efforts supported by a range of border agencies including DIMIA," the report said.
The report says 20.7 million air passengers arrived and departed in 2004-05, compared with 18.6 million the year earlier.
Of those air arrivals, 1,632 were refused airport immigration clearance, with 558 of them originating in Malaysia, a 30 per cent increase, and 171 from New Zealand, up 13 per cent.
Forty people applied for protection visas on arrival, compared to 23 in 2003-04.
In 2004-05, there were no unauthorised arrivals by sea, compared with 82 aboard three boats in 2003-04.