WASHINGTON (Reuters) - Sarah Palin, the 2008 Republican vice presidential nominee, called President Barack Obama a liar and urged her party to stand by conservative values, rousing the crowd at a conservative conference on Saturday.

"Barack Obama promised the most transparent administration ever. Barack Obama, you lie," the former Alaska governor said in an address to the Conservative Political Action Conference near Washington.

She was echoing a line from a Republican member of the House of Representatives who shouted at Obama during a speech to Congress in 2009 and accused him of lying about healthcare for illegal immigrants.

Palin's line drew a big round of applause from the audience, made up of Republican lawmakers and conservative activists.

She took aim at Obama's plans to push gun control legislation through Congress, including background checks for gun buyers.

"More background checks? Dandy idea, Mr. President. Should have started with yours," she said in a speech peppered with one-liners and folksy language.

Palin called on Republicans to stick to conservative principles as they learn lessons from Obama's 2012 election victory over Mitt Romney.

"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. That's a game we will never, ever win. We're here to restore America," she said.