Conservative Senator Vern White said he has asked the Senate's ethics officer to look into Merchant's role in the matter, saying there are "serious questions" to be dealt with.
CBC News first revealed last month that Merchant's husband, Regina class-action lawyer Tony Merchant, had shifted the funds in 1998 to an offshore trust based in the Cook Islands, in the South Pacific. Pana Merchant and the couple's three sons were all named as beneficiaries of the trust.
- Senator's husband put $1.7M in offshore havens
Merchant has never addressed questions from CBC News about her role in the offshore entity and whether she declared it confidentially, as required, to the Senate ethics officer.
White, appointed to the Senate last year after serving as Ottawa's police chief, said he wants Merchant to open up.
"Having no response satisfies no one," he said in an interview. "I think we all have a responsibility to start asking questions right now if we're going to hold each other to the same level of account the public wants us to be held to account."
The Senate ethics office said in a statement that its next step is to give Merchant a chance to respond. After that, Senate ethics officer Lyse Ricard will decide whether to launch a formal investigation.
Merchant's own caucus colleague, Liberal Percy Downe, has called for the Saskatchewan senator to provide answers about the offshore money.
"We're all innocent until proven guilty in this country, but I want to hear her explanation," Downe told CBC News in early April.
Merchant did not immediately respond on Tuesday to phone and email requests for an interview.
It is not illegal to move funds offshore or be the beneficiary of an offshore trust, however Canadians must declare all of their global income to the Canada Revenue Agency.
A tax expert previously consulted by CBC News said Tony Merchant's offshore dealings raised "some serious red flags." Tax-court filings obtained by CBC News showed that on his income tax return for 1999, the year after he established the offshore trust and put $1.7 million into it, Merchant ticked off the box for "No" when asked whether he owned more than $100,000 in "foreign property."
Under Senate rules put in place in 2005, Pana Merchant would have been required to confidentially declare that she was a beneficiary of the trust to the Senate ethics officer. But unless the officer deemed the information relevant to Merchant's parliamentary work, the public has no access to it.
The Senate has been embroiled for weeks in a scandal over the expenses claimed by four of its members. Former Conservatives Mike Duffy, Pamela Wallin and Patrick Brazeau as well as ex-Liberal Mac Harb have all seen their expense accounts audited amid claims they used taxpayer money improperly.
Duffy has had $90,000 of his expenses repaid on his behalf by Prime Minister Stephen Harper's then chief of staff, Nigel Wright, who resigned after the payment was revealed. Wallin has also repaid thousands of dollars, CBC News reported last week.
Harb and Brazeau are fighting orders to repay money.
Senator White maintained his decision to publicly call for an investigation into a Liberal senator was in no way an attempt to deflect from the scrutiny on his three former caucus mates, who now sit as Independents.
"I expect the public may say this is about partisanship. I can tell you it isn't, but at the end of the day the public will have to judge that."
If you have more information on this story, or other investigative tips to pass on, please email@example.comSuggest a correction