Both Republican and Democratic senators pressed for answers Sunday after revelations that President Barack Obama's pick for health secretary had to cough up over 100,000 dollars in unpaid taxes.
Tom Daschle, who would oversee Obama's campaign pledge to enact universal health care, faces a private hearing in front of the Senate Finance Committee Monday to explain the tax embarrassment.
The former Senate majority leader's nomination had been expected to be smooth sailing but now, Senate Republican leader Mitch McConnell said he would await Monday's hearing.
"I think I'm going to just wait until they give me their opinion," he told the CBS program "Face the Nation," adding: "But it was a surprise."
According to The New York Times, Daschle was aware as early as last June that he might have to pay back 128,000 dollars in taxes for the use of a car and driver provided by a private equity firm.
But he did not inform Obama's transition team until weeks after the then president-elect named him for the post of secretary of health and human services on December 11, the newspaper said.
Daschle's finances also reveal more than 300,000 dollars in income from health-related companies that he might have to regulate if he joins the Obama cabinet, it added.
Daschle, who says he has paid back the taxes plus interest, is the second Obama cabinet nominee to hit a snag over his financial affairs.
Timothy Geithner was confirmed as US Treasury secretary last Monday despite senators' misgivings over his failure to pay 34,000 dollars in US taxes while working for the International Monetary Fund earlier this decade.
Asked on "Fox News Sunday" how much trouble Daschle's nomination now faced, Senate minority whip Jon Kyl said: "I think it's too early to tell."
But "you have to be troubled by it," said the Republican, who sits on the Finance Committee.
Democratic Senator Ben Nelson said he was not yet prepared to drop his support for Daschle but told CNN "it's a tough issue."
It was important for the Finance Committee to probe the matter deeper, he said, "and I'll be paying attention to what they conclude once this meeting is over."