The rich are on "borrowed time", Jeremy Corbyn said as he took aim at their tax breaks and offshore havens.
At a rally at the World Transformed Festival, Mr Corbyn said the "poorest and most vulnerable" had been forced to pay the price for the 2008 financial crash.
The Labour leader said that winning an election is "not going to be easy" but hailed the power of "popular movements coming together".
Mr Corbyn was given a rapturous welcome at the festival, organised by the Momentum movement which backs his leadership.
He told the audience in Liverpool: "Challenging neoliberal economics is fundamental to what we believe in."
Mr Corbyn added: "Austerity has been meted out on the poorest and most vulnerable people in our society.
"They are the ones who paid the price of the banking crisis of 2008, all the time the very richest in our society have had tax breaks, giveaways and tax havens.
"I tell you what: they are on borrowed time because a Labour government is coming."