Hundreds of Hong Kong university and school students have gone on strike on the first day of classes after the summer break to show their commitment to the city's anti-government protests.

The school strike today was the latest act of defiance in a pro-democracy movement that has plunged the Chinese-ruled city into its biggest political crisis in decades.

At least 30,000 students from around 200 schools were expected to join the boycott, according to organisers. 

Hundreds have been arrested in violent clashes with police, and an increasingly shrill Beijing has labelled protesters 'terrorists', with an editorial by China's state news agency warning 'the end is coming'. 

The student protests follow a weekend marred by some of the worst violence since unrest escalated more than three months ago, with protesters burning barricades and throwing petrol bombs, and police retaliating with water cannon, tear gas and batons.