WASHINGTON – The Bush administration is focusing on a Social Security proposal that would allow younger workers to invest nearly two-thirds of their payroll taxes in private accounts, with contributions limited to about $1,000 to $1,300 a year, an administration official said yesterday.

A proposal is expected to be unveiled in late February. But the White House cautioned that President Bush has not decided on a specific plan.

The administration official, who spoke on condition of anonymity, said the size of the private accounts could be similar to a proposal by Senator Graham, a Republican of South Carolina, and a plan from Mr. Bush’s 2001 Social Security commission.

Both plans let workers divert 4 percentage points of their 6.2 percentage points in payroll taxes into accounts. The federal 12.4 percent payroll tax is split between workers and employers. Workers’ remaining 2.2 percentage points in taxes continue going into the system.

Mr. Graham’s plan calls for annual contributions to be capped at $1,300, while the commission proposed a lower limit of $1,000.

Mr. Bush “has not endorsed any specific proposal,” said White House spokesman Scott McClellan. “We are looking at a number of ideas for strengthening Social Security and will continue working closely with congressional leaders to move forward in a bipartisan way to get it done this year.”

To sell the idea of a Social Security overhaul – and private investment accounts – the administration plans to duplicate its successful campaign for tax cuts. At an event planned for Monday, Mr. Bush will meet with White House-approved people of varying ages to illustrate how changes to Social Security would affect different generations.

The strategy is similar to Mr. Bush’s efforts to gain support for his tax cut packages by featuring “tax families” and their financial situations.

“That’s the model,” said Michael Tanner, director of the Cato Institute’s Project on Social Security Choice. The libertarian think tank has been a longtime proponent of investment accounts.

“This is the way the president tends to campaign on these issues,” Mr. Tanner said, noting similar strategies for Mr. Bush’s Medicare and education plans. “He hasn’t lost one he wanted to win yet.”

Cabinet officials are stepping up their roles in the effort. Treasury Secretary Snow, Labor Secretary Elaine Chao, and others can be expected to visit communities across the country to bolster the administration’s desire for change.

Social Security is projected to start paying out more in benefits than it collects in taxes in 2018, though it can cover full benefits until 2042. Then, about 73% of promised benefits can be paid.

The administration so far has refused to discuss the difficult financial trade-offs required to remake the system.