Prank text messages sent to MPs phones via their public emails do not constitute hacking, Communications Minister Malcolm Turnbull says.

Ministers, including Attorney-General George Brandis and Environment Minister Greg Hunt, have been targeted by online activists campaigning against broader metadata storage laws and in Mr Hunt's case – for action on climate change. In one instance, Mr Hunt replied, asking "sorry who is this?"

Malcolm Turnbull Credit:Andrew Meares

Other MPs who have linked their public parliamentary email accounts to their iMessage accounts are thought to have also been targeted, with one source telling Fairfax Media the problem was widespread on Monday.