Arriving asylum seeker boats have set a record for the third straight month and September's influx has swamped the capacity of offshore processing centres.

A boat with 149 people found north of Ashmore Reef at the weekend took the month's tally to 35 boats carrying 2355 people - at least 250 more than the centres on Nauru and Manus Island could host when fully open.

The Gillard Government had hoped embracing Howard government-era policies seven weeks ago would stem the tide of arrivals, which are not only electorally poisonous but also a big drain on the Federal Budget.

But last month's arrivals surpassed the August influx of 34 boats and 1969 people and July's 31 boats with 1828 people.

Senior Government sources said yesterday the voluntary repatriation of 76 Sri Lankans in the past week was likely to stop many other Sri Lankans making the trip but that ethnic Hazaras from Afghanistan and Pakistan remained undeterred.

Shadow customs minister Michael Keenan said the Government's "half-hearted" approach to offshore processing emboldened people smugglers as shown by the arrival of 56 boats since Labor backflipped on Nauru in August.

"Surely, the Government must recognise that offshore processing on Nauru is not going to be enough to stop the boats from coming," he said. "They must reinstate the full suite of tough coalition policies to restore control of Australia's borders," Mr Keenan said.

The financial and operational pressures from people smuggling were highlighted by the Attorney-General and Corrective Services departments in annual reports to State Parliament last week.

One in 11 District Court hearing days were for people smuggling trials in 2011-12 and the number of people on outstanding people-smuggling charges had increased from 24 to 46 in the past four years.

Almost $60 million has been spent on housing accused and convicted Indonesian people smugglers in WA jails since 1985.

The Department of Corrective Services report said 112 accused and convicted people smugglers were in jail on June 30 - 2.3 per cent of the WA prison muster.

It said the people smuggler muster was 55 fewer than at June 30 last year but they still posed financial and operational challenges to meet cultural needs such as diet, interpreters and consular access.

The West Australian

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