The Liberal Party looks set to be forced to preferences in the blue-ribbon Sydney seat of Mackellar, as a new poll shows backbencher Jason Falinski faces a strong challenge from independent candidate Sophie Scamps.

Polling conducted in the Northern Beaches electorate this week shows Dr Scamps with 23.9 per cent of the first preference vote, behind Mr Falinski on 35.2 per cent. In 2019, he won 53.01 per cent of first preferences.