Ferguson makes the recommendations in his long-awaited audit of the expenses of senators, finally released today.
The report, which looked at 80,000 transactions worth a total of about $180 million, identifies nearly $977,000 in questionable spending over the course of a two-year window.
It also recommends the files of nine senators — seven retired, two still sitting — be referred to the RCMP for further investigation.
Ferguson says there's a lack of accountability and oversight in the Senate when it comes to spending taxpayer dollars, noting that senators often ignored more economical travel options.
Senate Speaker Leo Housakos, his deputy Nicole Eaton and Senate Liberal leader James Cowan, all of them among the other 21 senators, all say they will repay the expenses in question, although they dispute Ferguson's findings.