The Federal Government will introduce laws to make ISP-level filtering mandatory for all refused-classification material hosted overseas.
It will amend the Broadcasting Services Act next August to enforce the filter, which it expects to be operational within a year of implementation.
Grants will be made to providers that wish to further filter X18+ sites.
Announcing the measure today, Communications Minister Stephen Conroy said that the legislation would require ISPs to block RC-rated material hosted on overseas servers. He said it was an "additional measure to the existing take-down regime for Australia-hosted content".
Senator Conroy justified the filter, saying that "most Australians acknowledge that there is some internet content which is not acceptable in any civilised society".
"It is important that all Australians, particularly young children, are protected from this material," he said.
Senator Conroy said a pilot conducted by Enex TestLabs in conjunction with Australia's largest ISPs proved that such filtering was viable.
"The report into the pilot trial of ISP-level filtering demonstrates that blocking RC-rated material can be done with 100 percent accuracy and negligible impact on internet speed," he said.
The Government announced that the list of blocked RC content would be compiled "through a public complaints mechanism".
But these public complaints will only form a subset of the total content blocked. The Government will also add "specific internet addresses (URLs) of known child abuse material through sharing lists with highly regarded international agencies after an assessment of the rigour and accountability of classification processes used by these agencies".
The Government said it was "also introducing new transparency measures to ensure the public can have absolute confidence in the process for material being placed on the RC Content list" but is yet to release details.
It is believed the mechanism for this process will be hammered out during the consultation phase over the next few months.