House Ways and Means Committee Chairman Dan Rostenkowski (D-Ill.) and Sen. Bill Bradley (D-N.J.) criticized the Reagan administration yesterday for postponing the announcement of its revised tax-simplification plan from Monday until May 28.

Rostenkowski and Bradley said the additional time gives special interests a chance to seek more loopholes in the plan, which is intended to be fairer than the current tax code by lowering rates and wiping out numerous tax breaks.

Rostenkowski said in an interview that his schedule of hearings in the summer and bill-writing in the fall would not be speeded up to accommodate the slippage.

"You can spend all the time you want romancing the president," Rostenkowski said he told Treasury Secretary James A. Baker III Wednesday, "but I've got to romance 435 members of Congress . . . . I'll be damned if I'll have anybody tell me, 'You closed the door on public participation.' "

Bradley told reporters that "the longer they delay, the more likely that it is going to be filled with provisions that invite a Christmas tree. It doesn't sound a good signal and I think it's a trap laid by special interests."

The White House said the announcement was postponed at the request of Republican congressional leaders, who worried that it would deflect attention from the House debate on the budget and lead to an unwanted tax increase rather than the politically painful cuts in domestic programs President Reagan wants.

Meanwhile, administration sources said officials are considering a smaller increase in the standard deduction than proposed by the Treasury Department last November.

Treasury originally proposed a standard deduction for single persons of $2,800, up from the current $2,510. For married couples the deduction was to be $3,800, up from $3,710, and for single heads of household, the deduction would have been $3,500, up from $2,510.