Brown keenly aware of GOP status in Mass.

In a speech to the Greater Boston Chamber of Commerce that mixed politics and policy, Brown, a Republican, said that Washington has wasted too much time on fluff at the expense of cutting taxes and spending, and that he considers himself an underdog for reelection in 2012.

Brown asserted that Congress has devoted only 12 days to job creation since he took office in February. To reinvigorate the economy, Congress must cut payroll taxes, preserve tax credits for research and development, and extend Bush-era tax cuts, which are set to expire at the end of this year, Brown said.

“Now the election’s over, but we can’t go back to business as usual,’’ he told the breakfast meeting at the Boston Park Plaza Hotel. “I can’t go back to Washington later today and start working again on fluff, when we should be focusing on the very important things that can get our country and our state moving again.’’

The senator, making his first appearance at the chamber since his election in January, was greeted warmly, if not enthusiastically, by the crowd of business leaders. Surveying the audience, Brown said he saw many who supported his campaign for US Senate, and many who didn’t.

“The didn’t is more than the did,’’ he chuckled. “That’s OK.’’

Brown spoke at a tough time for Massachusetts Republicans, who lost every statewide and congressional race on Nov. 2. The senator, who backed many of the unsuccessful candidates, focused instead on his party’s national success and its imminent takeover of the US House and gains in the US Senate.

“I’m hopeful, now that voters have spoken, that this Congress and the administration will say: ‘Message received. We get it,’ ’’ he said, pounding his lectern. “ ‘We’re going to get back to work.’ ’’

“Congress needs to narrow its focus and do it right away,’’ Brown added. “Washington has left you, the job creators, in limbo, waiting for answers, waiting for certainty.’’

After his 30-minute speech, Brown took several questions from the audience but dodged some reporters by leaving quickly through a service entrance.

He sidestepped a question about the controversial combination of deep cuts to Social Security and Medicare and big tax increases that the chairmen of President Obama’s deficit reduction commission recommended last week. “It’s clear we need to do something,’’ Brown said, but did not elaborate.

He said “modification in some form’’ is needed to ensure that the new federal health care law does not hurt the economy, but he stopped short of saying it should be repealed. “I believe everyone is entitled — should get some form of basic health care,’’ but it should be provided by the states, he said.

Brown is perhaps the state’s most popular politician, according to polls, but he acknowledged that Massachusetts Democrats, newly energized by their sweep on Nov. 2, are eager to unseat him in 2012.

Brown joked that he would begin his reelection campaign immediately after his speech and would be standing outside, in his trademark barn jacket, with his pickup truck and Curt Schilling by his side, shaking hands with voters.

“It’s been like 17 years, and I’m always the underdog,’’ said Brown, a former state lawmaker. “I get it. I am a Republican from Massachusetts. I have the scars to prove it. But I’m focused on doing this job, and I’m honored to have the opportunity to do it.’’

Brown said he was proud to have been targeted by groups of protesters across the political spectrum, calling it proof that he is fulfilling his promise to be “an independent thinker and voter.’’

Brown, pressed by chamber president Paul Guzzi to discuss his prospects for reelection, seemed to tire of the subject.

“Give me a break, really,’’ the senator said. “The time for running for election will be here soon enough, in another year or so. You know whose jobs I’m worried about? Yours. I’m worried about yours and the people who work for you.’’

Michael Levenson can be reached at mlevenson@globe.com.