The two Labour leadership candidates from the region have clashed over changing how MPs are selected.
Rebecca Long-Bailey, who represents Salford and Eccles, told supporters at a hustings in Bristol that she would bring in open selections if she was elected leader.
The move would make it easier for local party branches to deselect sitting MPs before elections.
"Being an MP is not a job for life," said Ms Long-Bailey.
But Wigan MP Ms Nandy told the audience she disagreed with her rival's views.
"The MPs I want to get rid of are Tories, not Labour," the former shadow energy secretary said.