WASHINGTON — Maine Sen. Susan Collins on Wednesday blasted what she called “outrageous” examples of wasteful spending at the General Services Administration, a federal agency that is supposed to promote greater government efficiency.

Collins and other lawmakers on Capitol Hill have been probing the GSA ever since April when the Inspector General released a report detailing a lavish conference in Las Vegas in 2010 for employees and managers in Western states that cost the government more than $800,000.

Since then, lawmakers have also raised concerns about employee awards and bonuses within the agency, wasteful travel and numerous instances where the GSA – which is in charge of procurement for the federal government – didn’t even follow its own policies.

On Wednesday, the Senate Committee on Homeland Security and Governmental Affairs held a hearing to ask GSA officials about how things are changing at the agency, which in addition to procurement manages federal buildings and other properties.

Collins, who along with Connecticut Sen. Joseph Lieberman has been leading the probe into the GSA, said that her committee has since learned additional details of what she said were disturbing expenditures. Those included five- to six-day trips to Hawaii for a one-hour ribbon cutting, $30,000 for drumsticks used in a teambuilding exercise and awards exceeding $50,000 to employees.

“This is outrageous and particularly so in the midst of what is supposed to be a freeze on pay in the federal government … a bad economy and high unemployment,” said Collins, ranking member on the committee.

Collins credited the GSA’s Acting Administrator Daniel M. Tangherlini, who took over in April after Adminstrator Martha Johnson resigned amid the scandal, for conducting a thorough review of the spending. But she added: “The review must result in lasting, sustainable reforms. Not one more dollar at this agency can afford to be wasted.”

Nearly a dozen managers responsible for organizing the Las Vegas conference have since been fired while other employees have been suspended or required to reimburse the department.

Tangherlini told senators on Wednesday that he has also taken other steps, including centralizing review of all conferences, scaling back employee travel, reducing awards to senior administrators by 85 percent and a targeted hiring freeze.

He called what happened at the Las Vegas conference “a complete waste of taxpayer money,” adding that such practices have no place in any federal agency but are “particularly at odds” with the GSA’s mission.