Corbyn is expected to give a speech to his supporters at a rally in Milton Keynes, which is being held on Saturday.
"Using our mass membership we can organize within communities and communicate with voters in a more effective way than ever before. With over half a million members, Labour can be at the heart of every community in Britain and win the next general election," he will say according to BBC broadcaster.
In June, Corbyn faced a motion of no confidence and saw half of the shadow cabinet resign in protest at what they claimed was his inability to lead the main opposition party after the Brexit referendum. Corbyn refused to resign and said he would take part in the party leadership election. Corbyn is competing against Owen Smith amid mounting criticism of the former.
