Two Manitobans are on a list of nine senators whose expense files are being sent to the RCMP because of a forensic audit that has flagged more than 970-thousand dollars in questionable spending.

Sources have told The Canadian Press that former senators Sharon Carstairs and Rod Zimmer are on the list.

Carstairs is a former Liberal government Senate leader who used to teach new senators about the expense rules to ensure they didn't make mistakes.

Zimmer is also a former Liberal senator. He attracted media attention in 2012 after an incident aboard an Air Canada flight involving his wife, Maygan Sensenberger.

In addition to the nine individuals being referred to the RCMP, 21 other sitting and former senators will be compelled to repay questionable expenses.

Manitoba conservative senator Janis Johnson is one of the 21 senators flagged.

Johnson wrote on her website defending her spending habits and the accusations.

In the online post, Johnson said she will follow the arbitration process and will repay expenses if she's found to be in the wrong, but said she's confident her spending is legitimate.

"I can assure you that throughout my 25-year tenure as a senator that has always been forefront on my mind. I have rarely used all of my allowable travel points, and in the period under review (March 2011 - April 2013), I used less than half the travel points permitted," Johnson wrote.

"I have followed the senate travel policy scrupulously and that the auditor general has come to a wrong conclusion in my case," said Johnson.

- with files from The Canadian Press