Tkachuk is the former chair of the Senate committee that ordered the audit of Wallin.
Wallin told reporters Monday that she was advised to include only relevant information in her calendar when handing it over to Deloitte auditors, and so she omitted some items.
Postmedia News reported that it was Tkachuk who gave her that advice and that auditors found details about a Conservative riding association fundraiser in 2009 that had been removed from her calendar but existed in backup files.
Tkachuk defended his actions on Tuesday, saying he never told Wallin to do anything wrong.
"It makes no sense whatsoever," Tkachuk said Tuesday morning when asked about Wallin's calendar changes. "I didn't ask her to change her calendar, all I did was I said when you submit your calendar I said make sure you put in relevant material and not irrelevant material."
Tkachuk made the comments on his way into the Senate's internal economy committee meeting. The committee is meeting to discuss the report written by a subcommittee in response to the Deloitte audit on Wallin that was given to the members, and to Wallin, on Monday.
Could refer matter to RCMP
The committee will either accept the report as written, or make amendments to it. It could contain several recommendations, including a referral of the audit to the RCMP.
Senator Gerard Comeau, who replaced Tkachuk as the committee chair, said the subcommittee report consists of about five to six pages. He would not comment on his way into the meeting on what it said.
The Senate report and details of the Deloitte audit will be released later in the day. Wallin has already paid back $38,000 for expenses she said were claimed in error. CBC News reported Monday that the audit identified ineligible expenses worth about $120,000. A further $20,000 in expenses were identified as "subject to interpretation," and the audit recommends the Senate decide whether they should be accepted or not.
Wallin pledged Monday to pay back every dollar she is asked to, with interest, but she disputed the audit process, calling it "flawed and unfair." She also said she never tried to mislead auditors by adjusting her calendar.
Tkachuk was clear that he didn't tell her to remove any fundraising events, nor did he advise her on what was relevant or not for the auditors to see.
"I never told her to do anything like that," he told reporters. "All I told her was to make sure her calendar was clean. The audit was taking a long time, I wanted to move it ahead … it was a passing comment in an hour-long conversation where I said make sure you submit what you have to submit and leave all the irrelevant material off your calendar.
"If she did something wrong, no one told her to do it, certainly not me. I was chair of the audit committee. I was trying to move the process along, and I never ever told her to omit anything that was relevant.
He said it was up to Wallin, not him, to decide what was relevant, and he suggested that party fundraising events are items that would be relevant if she claimed expenses for them.
'Serious concerns' about audit
Wallin told reporters Monday that she only sought reimbursement for travel expenses she thought were proper and that where she had made mistakes, she has paid money back.
She also said the auditors were retroactively applying rule changes made in 2012 to expenses she claimed between 2009 and 2011 that were all approved by the Senate at the time. Now they are being disallowed, she said.
The Saskatchewan senator and former journalist said she has "serious concerns" about the audit but that she no longer wants the matter to be a burden and wants to focus on causes close to her heart.
The Deloitte audit took more than six months to complete and was delayed because it originally looked at an 18-month period and then went further to examine Wallin’s expenses since the time she was appointed by Prime Minister Stephen Harper in 2009.
Audits were also done on senators Patrick Brazeau, Mike Duffy and Mac Harb and were released in May. They focused more on their housing allowance claims than travel expenses. The RCMP is investigating all three senators for breach of trust.
Duffy is also being investigated for the $90,000 cheque written by Harper’s former chief of staff Nigel Wright to cover his repayment to the Senate. Harb has been asked to pay back $240,000,and Brazeau has been asked to pay back $48,000. They are disputing the orders. No charges have been laid against any of the senators.
Comeau, chair of the internal economy committee, said he has confidence that senators are following the rules and that the Senate is doing ongoing spot checks of their finances.