Acting special minister of state Gary Gray announced on Friday that the government would close an ''insurance gap'' that left Mr Slipper subject to legal costs resulting from the Federal Court action.

The gap arose because the civil proceedings began before a new management liability insurance scheme for federal MPs and senators started on July 1. Mr Gray said he had decided to use an ''act of grace'' mechanism to cover the gap in insurance coverage, following a request from Mr Slipper.

This means the government will pay Mr Slipper's net legal costs from the Federal Court matter and the subsequent appeal.

Mr Gray would not estimate how much it could cost the federal government, although he added that it could cost the Commonwealth nothing.

''We sincerely hope that that is the case,'' he said in Perth.

Last December, Mr Ashby's civil case against Mr Slipper was dismissed by the Federal Court, with Justice Steve Rares finding the case, based on allegations of sexual harassment, was an ''abuse of process''.

Mr Ashby is appealing on several grounds, including that the judge erred in his findings.

Mr Ashby's solicitor, Michael Harmer, has also appealed.

With AAP