Australian actress Toni Collette has joined Concern Worldwide as the humanitarian organisation's first Global Ambassador.

The Sixth Sense star will use her profile to raise awareness of the charity's campaigns to help the world's poorest people.

As part of her duties, Collette will travel to 25 countries across Africa, Asia and the Middle East to witness the organisation's work first hand.

She says, "I am deeply honoured to join Concern as their first Global Ambassador. I know I am becoming part of a global team of men and women committed to transforming care and empathy into real, direct and effective action that creates lasting change in the lives of some of the world's poorest people."