While political operatives are focusing intently on the country's most marginal seats, excitable chatter is mounting about one of its safest: former prime minister Tony Abbott's seat of Warringah.

With Mr Abbott sitting on a margin of 15 per cent, local campaign workers are not doubting he will be returned, but speculation is growing that he may face a "scare" at Saturday's poll in the form of a sizeable swing against him.

For a man whose supporters are talking up a second act in Australian public life, the size of the swing in Warringah will inevitably be compared with the average and picked over more than most others.