David Langtry, who is now acting chief and formerly served as deputy chief of the commission, has accumulated bills totalling nearly $760,000 for flights, accommodation, taxis, meals and other expenses since 2006.
Langtry lives in Winnipeg, and commutes to the commission's offices in Ottawa.
Aaron Wudrick, the federal director of the Canadian Taxpayers Federation, wants to know how this situation happened.
"The question is why did the government even put that offer on the table. This is a very unique situation," he said. "You have an individual living 2,000 kilometres away for a very prestigious federal appointment and because of that, taxpayers have been on the hook."
The NDP's Charlie Angus also has questions about Langtry's expenses.
"When we appoint qualified people, they should be willing to take the job and they should move there and if they have expenses, that's all fair, but you don't get to commute," Angus said.
Government will review costs
Justice Minister Peter MacKay said the government is looking into Langtry's expenses.
"It is a significant bill and it is taxpayers' money, so for sure, we have to verify all of those expenses and ask hard questions," MacKay said.
A spokesman for the commission said Langtry wasn't available for an interview on Thursday, but said his expenses are consistently disclosed as per Treasury Board requirements and meet guidelines on travel and hospitality.
David Gollob also said the government was aware Langtry lived in Winnipeg when he received the green light for the job.
Wudrick wants the Conservative government that appointed Langtry to provide an explanation.
"The government made him the offer," Wudrick said. "We would be concerned if this became the standard. Is this going to set a precedent?"