Former US vice presidential candidate Sarah Palin took center stage to speak before conservative activists Saturday, needling President Barack Obama and even fellow Republicans.

"We don't have leadership coming out of Washington, we have reality television, except it's really bad reality TV, and the American people tuned out a long time ago," Palin told the Conservative Political Action Conference, known as CPAC, held near Washington.

Palin, a former Alaska governor who was John McCain's running mate in 2008, has since served as contributor for the Fox News channel and even starred in her own reality show in 2010.

"Mr President, we admit it, you won, accept it. Now step away from the teleprompter and do your job!" she said in a swipe at Obama.

"Barack Obama promised the most transparent administration ever. Barack Obama, you lie."

Palin then caused the crowd to erupt in laughter and applause by taking large sips from a Big Gulp cup filled with soda in reference to New York Mayor Michael Bloomberg's attempt to ban such oversized sweet drinks.

His plan, opposed by conservatives in the name of individual liberties, was blocked by a New York judge this week.

However, the sharpest attacks by the self-styled "Mama grizzly" were aimed at the head of her party, accused of trying to marginalize ultra-conservative "Tea Party" candidates in primaries for November 2016 elections.

"We're not here to dedicate ourselves to new talking points coming from (Washington) DC," Palin said.

"We're not here to put a fresh coat of rhetorical paint on our party. We're not here to abandon our principles in a contest of government giveaways.

"The last thing we need is Washington, DC vetting our candidates," she fumed, before lashing out at political consultants who advise on Republican Party strategy.

"Now is time to furlough the consultants," she added. "These experts keep losing elections and keep getting rehired and raking in millions."

Palin has long nursed a grievance against party strategists following her team's presidential election loss, when she had sharp disagreements with John McCain's campaign staff.