The plan -- which passed 228 to 191 Thursday, with no Democratic votes and 10 Republican defections -- gives millionaires and billionaires "a massive tax cut" paid for by "ending Medicare as we know it," the White House said after the vote.
Obama will tell the American Society of News Editors convention in Washington Tuesday the nation can't afford to go down that road, administration officials told reporters.
Obama's luncheon talk -- continuing themes he advanced in a Osawatomie, Kan., speech in December and in his State of the Union address in January -- was to begin at 12:30 p.m. EDT, the White House said Monday night. It was to be followed by questions and answers.
The GOP plan, introduced by House Budget Committee Chairman Paul Ryan, R-Wis., would turn the Medicare government insurance program for Americans age 65 and older into a subsidized set of private insurance plans, with an option letting current Medicare recipients buy into the existing fee-for-service program. Medicare's budget would be cut $205 billion below Obama's budget through 2022.
Other health programs, including Medicaid for low-income people and people with disabilities, would be cut $770 billion.
Entitlement programs -- including welfare, food stamps, agriculture subsidies and transportation -- would be cut nearly $2 trillion.
Ryan said after his plan passed it would be an asset to the GOP's presidential nominee because it shows what the party would do with control of Congress and the White House.
"People deserve to be spoken to like adults," Ryan sad.
Front-running Republican presidential hopeful Mitt Romney endorsed the Ryan plan.
Obama planned to tell the editors, producers or news directors Tuesday -- the day of three primaries that could make Romney the presumptive nominee -- that if a future Republican president enacts a budget that resembles Ryan's plan, middle-class Americans would be hit especially hard, and the fragile economic recovery could stall, the officials said Monday.
"Should we ask middle-class Americans to pay even more at a time when their budgets are already stretched to the breaking point? Or should we ask some of the wealthiest Americans to pay their fair share?" Obama said Saturday in his weekly radio and Internet address, foreshadowing his Tuesday address.
"For too long, the U.S. tax code has benefited the wealthy and well-connected at the expense of the vast majority of Americans," the White House Web site says under the headline "Restoring Fairness."
"That's why President Obama has successfully fought to cut taxes for middle class families and small businesses. And it's why he has called for reforming our tax code and closing tax loopholes for millionaires and billionaires as well as hedge fund managers, private jet owners and oil companies," the Web site says.
Obama was expected to say Tuesday tax-system fairness includes implementing the so-called Buffett Rule, scheduled to be voted on this month in the Senate, where Democrats are the majority party.
The rule, named after billionaire U.S. investor Warren Buffett, would seek to ensure that people earning more than $1 million a year pay a minimum effective tax rate of at least 30 percent, "implemented in a way that is equitable, including not disadvantaging individuals who make large charitable contributions," the White House said.
"The wealthiest Americans are paying taxes at one of the lowest rates in 50 years. Warren Buffett is paying a lower rate than his secretary," Obama said Saturday.
"Do we want to keep giving tax breaks to the wealthiest Americans like me, or Warren Buffett, or Bill Gates -- people who don't need them and never asked for them?" Obama said. "Or do we want to keep investing in things that will grow our economy and keep us secure? Because we can't afford to do both."
"Now, some people call this class warfare," Obama said, disputing Republicans' claims he was practicing the politics of division. "But I think asking a billionaire to pay at least the same tax rate as his secretary is just common sense. We don't envy success in this country. We aspire to it. But we also believe that anyone who does well for themselves should do their fair share in return, so that more people have the opportunity to get ahead -- not just a few."