Windsor, Oakeshott spoke to Slipper

Key independents Tony Windsor and Rob Oakeshott have revealed they encouraged Peter Slipper to resign as Speaker before they sided with Labor to prevent him being sacked.

The two NSW independents said they counselled him for an hour about his "options" as Tony Abbott railed in Parliament on Tuesday against Mr Slipper's suitability for the high office.

"(We) suggested to him maybe the proper thing to do was that he consider resigning and he did that," Mr Windsor said yesterday.

They told him his position was untenable in light of crude text messages he sent to his former staffer James Ashby, who is suing Mr Slipper for sexual harassment.

"It was essentially an ultimatum. We were reluctant to support a vote (to oust him) which would have been the first in the history of our Parliament," Mr Windsor said.

Mr Oakeshott said he had been of the view for a "long time" that Mr Slipper should resign and that the evidence in the Federal Court had only confirmed this view. Deputy Opposition Leader Julie Bishop said the independent MPs had been party to "another grubby deal".