The indefinite bridging visas - which will apply to arrivals after the August 13 announcement of offshore processing - will put refugees on the same basis regardless of whether they are processed in Australia or on Nauru or Manus Island.

The visas are just a step short of the Howard government's harsh temporary protection visa system - under which refugees could be repatriated to their home countries if conditions allowed.

The fresh crackdown follows a continued big inflow of asylum seekers - more than 7500 since August 13 - with no sign that offshore processing is acting as a deterrent.

Immigration Minister Chris Bowen conceded that, given the numbers, it would not be possible to transfer all of them to Nauru or Manus Island in the immediate future.

Under an extension of the ''no advantage'' test, Mr Bowen said these people would not get permanent visas until they had waited as long as if processed offshore. The wait on bridging visas could be as long as five years, he said.

In other actions, the government has transferred the first asylum seekers to Manus Island - seven Sri Lankan and Iranian families including four children, the youngest aged 10 - and announced an expansion of accommodation on the Australian mainland to cope with the numbers.

Capacity at the Melbourne Immigration Transit Accommodation will be increased by 300 places and the Pontville site near Hobart will be re-opened.

Amid hunger strikes and self-harm by asylum seekers on Nauru and searing criticism by Amnesty International of their conditions, Mr Bowen said processing of claims there was expected to fully begin early next year. He said that if Amnesty had constructive suggestions ''we will listen to them, but they have a fundamentally different approach''.

Specialised children's services on Manus Island will be provided by Save the Children, including child protection and education activities.

Meanwhile, another 100 Sri Lankan men were sent home on Wednesday, bringing to 426 the number of Sri Lankans returned involuntarily since August 13. When voluntary returns are included, 525 Sri Lankans have gone back. There has been a spike in those coming from Sri Lanka and the government says many are driven by economic reasons rather than the fear of persecution.

Mr Bowen said that people processed in the Australian community and put on to bridging visas ''will have no work rights and will receive only basic accommodation assistance''. A single man will get a basic payment of 89 per cent of the lowest Centrelink payment - about $438 a fortnight - plus 89 per cent of rent assistance, or a maximum $107.69 a fortnight.

''It's not a generous allocation, but it's an appropriate allocation that means that they can, obviously, provide for the basic needs that they have,'' Mr Bowen said.

He said ''no one should doubt this government's resolve to breaking the people smugglers' business model and save lives at sea''.

The Coalition and the Greens combined in the Senate on Wednesday night to disallow a government regulation that would have enabled public servants to roll over bridging visas rather than having to go back to ministers for renewal.

Opposition immigration spokesman Scott Morrison said the government ''just hands out welfare and entry permits to people who come on boats now''.

He slammed the government's failure to set up permanent facilities on Nauru. ''The government has not even laid a slab,'' he said. Mr Bowen said a contract has been signed for work on the permanent facilities on Nauru.

Opposition Leader Tony Abbott, who is committed to even tougher policies including temporary protection visas, dismissed Amnesty's criticism of conditions on Nauru. ''People who come illegally to this country can't expect to be treated like they're staying in a four-star or a five-star hotel,'' he said.

Greens leader Christine Milne accused Mr Bowen of ''an appalling shift back to even worse and more extreme'' treatment of people than John Howard's approach.

Refugee Council of Australia chief executive Paul Power said the government was ''tying itself in knots'' to make the no-advantage test work.

Amnesty International campaigns director Andrew Beswick said: "This milestone marks yet another attempt by the federal government to create an elaborate plan to punish vulnerable people for seeking safety and protection and squibs our responsibilities under the UN Refugee Convention.''

Pamela Curr, of Melbourne's Asylum Seeker Resource Centre, said Labor was ''winding back everything they stood for while they were in opposition''.