Kevin Rudd was so poll driven as prime minister that he once asked Labor's national office to conduct research on what his ''one core belief'' should be, a new book by Wayne Swan reveals.

Mr Swan has also revealed that Mr Rudd asked him on May 14, 2010 - more than a month before he lost the nation's top political job on June 24 - ''if you are with me?'' as the prime minister became increasingly ''jittery'' and his leadership began to ''wobble''.

Kevin Rudd: became increasingly "jittery", according to Wayne Swan.

Mr Swan says he and other senior ministers put Mr Rudd on notice for six months that his government was drifting, before the leadership change. Eventually, a story on June 23 by Sydney Morning Herald political editor Peter Hartcher created a ''political earthquake'' and the change occurred.