It's been a huge day for more than 300,000 Australian school and university students, families and workers who took to the streets of their cities and towns to protest climate change inaction.

Up to 80,000 people are estimated to have poured into The Domain in Sydney. Credit:Louise Kennerley

Organisers described the turnout as the biggest nationwide since 500,000 people protested against the Iraq war in 2003. Similar school strikes in March and November last year drew 40,000 and 15,000 people.

Police commended the large crowds for displaying good behaviour at the peaceful protests.