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 Tuesday.

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 size of the private accounts could be similar to a proposal by Sen. Lindsey Graham, R-S.C., and a plan from 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.

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

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, the administration plans to duplicate its successful campaign for tax cuts. At an event planned for Monday, Bush will meet with White House-approved people of varying ages to illustrate how changes would affect different generations.

The administration so far has refused to discuss the difficult financial trade-offs required to remake the system. For example, any proposal offered will cut traditional benefits for younger workers to help fund the future shortfall. Also, the administration must identify $800 billion to $2 trillion over 10 years to continue funding retirees benefits once the payroll taxes are diverted into accounts.

Under the plan offered by Bush’s commission, promised benefits would be cut almost in half for some younger workers, with reductions ranging from 0.9 percent to 45.9 percent. Investments in the personal accounts are counted on to make up the loss in income.