A Liberal Party Senator has angrily demanded an explanation as to how the ABC decides which organisations should be described as terrorist groups.

ABC executives have been giving evidence at a Senate estimates hearing in Canberra.Liberal Senator Michael Ronaldson has lashed out over the broadcaster's use of the word terrorist."I'll ask you again, is Hamas a terrorist organisation or not?" he said."If it's not, what's changed between the last Senate estimates and now."The ABC's managing director, Mark Scott, told the hearing the broadcaster's editorial policies include a preference to avoid labelling organisations, unless it provides valuable information or context."Hamas, Hezbollah and Islamic Jihad might well be described as terrorist groups, if they commit terrorist activities, but what I've indicated to you, that it does not automatically mean they'll be referred to as a terrorist group or a terrorist organisation in every story," he said.