The Coalition has re-awakened internet filtering just two days before the federal election, revealing plans to make ISPs and mobile telcos filter services "by default" unless proof of age is supplied.

Update: 9:30pm - Shadow Communications Minister Malcolm Turnbull has scrapped the internet filtering policy, mere hours after endorsing it on live radio. He described the policy document as "poorly worded."

The policy comes despite Opposition Leader Tony Abbott's 2010 pronouncement there was no proof ISP filtering works.

A policy document "to enhance online safety for children" was quietly posted to the Liberal party website today, providing scant detail on the sudden resurrection of filtering. (pdf)

The party said its proposal "is a very different approach to the discredited compulsory filter proposal championed by the Rudd-Gillard Government, which was abandoned as unworkable".

It said it would work with internet service providers to "develop online safety standards" for fixed line broadband services into homes.

It went on to define "standards" as involving "the major internet service providers providing home network filters for all new home broadband services".

These filters would be switched on as the default unless the customer specifies otherwise, or proves they are over 18, the Coalition said.

Parents would be "empowered" to choose whether or not to maintain the filter settings on their home internet connection, though "maximum protection" would be provided by default.

Smartphone users under the age of 18 would have "adult content filters" applied to their mobile services by default, according to the policy.

The Coalition said it would work with mobile phone operators to install the filters onto handsets.

It also plans to introduce legislation to force social media sites operating in Australia to take down "harmful material" quickly.

The Coalition said it would define specific rules for the takedown system within six months of coming to power.