PETER Slipper's accuser, his former staffer James Ashby, has abandoned criminal allegations in his civil case that the Speaker of the House of Representatives misused Cabcharges.

Mr Ashby's lawyers lodged a statement of claim late yesterday that omits allegations from his originating application concerning Mr Slipper's alleged misuse of Cabcharge dockets in January and February 2012.

It followed a pre-emptive move by the Commonwealth that sought to strike out Mr Ashby's Cabcharge fraud allegations in the civil harassment case ''on the ground that it discloses no reasonable cause of action''.

The legal manoeuvres by Mr Ashby and the Commonwealth come before a directions hearing on the case in the Federal Court on Friday.

A statement last night by Mr Ashby's spokesman said the fraud allegations were dropped in the civil case because Mr Slipper now faced a separate criminal investigation. Mr Ashby was now providing assistance to the Federal Police, as a witness.