Former Liberal prime minister Malcolm Fraser has joined the surge of former leaders on the campaign trail - saying bluntly the Coalition is not ready for government.

While the toppled Labor leader Kevin Rudd yesterday tried to come to the Gillard government's rescue - and John Howard told the Coalition faithful they could really win the August 21 poll, Mr Fraser was much more downbeat.

Mr Fraser, who quit the Liberal Party late in 2009, said the Coalition was not ready to govern the nation.

When asked for his reasoning, however, Mr Fraser told ABC Radio: ''Read my book.''