The Coalition has rowed back from a policy announced earlier on Thursday to install opt-out internet pornography filters on home computers and under-18s' mobiles.

Malcolm Turnbull, the shadow communications minister, tweeted on Thursday evening: “Policy released today wrongly indicated we supported an opt out system of internet filtering. That is not our policy and never has been.”

Policy released today wrongly indicated we supported an opt out system of internet filtering. That is not our policy and never has been. — Malcolm Turnbull (@TurnbullMalcolm) September 5, 2013

This was followed by a longer statement from Turnbull stating: “The Coalition has never supported mandatory internet filtering. Indeed, we have a long record of opposing it.”

He added: “The policy which was issued today was poorly worded and incorrectly indicated that the Coalition supported an ‘opt out’ system of internet filtering for both mobile and fixed line services. That is not our policy and never has been.”

He said the true Coalition position was to encourage mobile and internet service providers to “make available software which parents can choose to install on their own devices to protect their children from inappropriate material”.

The policy document released earlier on Thursday said internet service providers would apply the filters to all home wifi and under-18s’ smartphones, with people having to opt out if they did not want them.

On the campaign trail on Thursday evening, Tony Abbott apologised for the mix-up and repeated Turnbull's description that the original policy had been "poorly worded".