A leading senator with oversight of the General Services Administration said he wants the agency’s watchdog to conduct a broader investigation of its spending on conferences and that he plans to hold hearings on how top officials are managing the scandal.

Sen. Joseph I. Lieberman (I-Conn.), chairman of the Senate Homeland Security and Governmental Affairs Committee, said Sunday that his panel is asking GSA Inspector General Brian D. Miller to look into spending in all of the agency’s regions, after Miller exposed more than $820,000 in spending on a Las Vegas conference held by GSA’s Region 9 in October 2010.

Lieberman said he wants Miller to investigate the other regions “to make sure that there’s no similar behavior such as what we found in Region 9.” Speaking on “Fox News Sunday,” the senator said his committee also plans to hold hearings “that will call in the leadership of GSA to make sure they’ve taken a good hard look at how GSA does business.”

GSA officials implicated in the scandal “were living in some strange bubble,” Lieberman said. Worse, he said, the spending scandal — coupled with an unfolding sex scandal involving Secret Service employees and military personnel — reinforces negative perceptions of the nation’s federal employees.

“When the economy is down, when people are struggling to pay their bills, when they’re struggling to pay their taxes — it’s outrageous that federal employees did this,” Lieberman said.

“As somebody who spent a lot of my life in government, I get sickened by these kinds of stories from Secret Service and GSA,” Lieberman said. “They don’t reflect what I know to be the typical federal employees, but they do nothing but increase the cynicism that the American — and anger that the American people feel toward their government. And that’s just bad for our democracy.”