Australia's "largest maritime operation" in peacetime history will involve up to a dozen patrol boats and a supporting naval warship, as well as an offshore patrol vessel from the Australian Border Force (ABF), to create a so-called "ring of steel" to block future people-smuggling ventures.

Key points: PM confirmed exercise in northern waters in preparation for asylum seeker boats surge

PM confirmed exercise in northern waters in preparation for asylum seeker boats surge Six Royal Australian Navy Armidale Class ships are already deployed to north

Six Royal Australian Navy Armidale Class ships are already deployed to north Christopher Pyne declines to say which ADF and ABF assets are used

The unprecedented exercise in Australia's northern waters was confirmed by Prime Minister Malcolm Turnbull over the weekend in preparation for a possible surge in asylum seeker boats as a result of the United States refugee resettlement deal.

Military sources have confirmed to the ABC that six Royal Australian Navy Armidale Class ships are already deployed to the north, and will soon be joined by a major fleet support unit, which could be either an ANZAC-class warship or a guided missile frigate.

The Royal Australian Air Force is also contributing to the huge operation with surveillance assets such as P3-Orions.

As well as the substantial military involvement, the ABF is sending up to half a dozen of its Cape Class patrol boats which will be supported by an offshore patrol vessel.

One source familiar with the operation has confirmed other government agencies, including the Australian Secret Intelligence Service, are involved in the effort.

Six Royal Australian Navy Armidale Class ships are already deployed to the north. ( Supplied: Department of Defence, file photo )

Earlier today, Defence Industry Minister Christopher Pyne declined to say which Australian Defence Force and ABF assets were being used.

"In terms of our deployment north of Australia — that's classified information," Mr Pyne told reporters.