The Bush administration Wednesday unveiled long-promised legislation setting up a system of tax credits to help low-income parents make child-care arrangements.

President Bush's proposal, outlined by Press Secretary Marlin Fitzwater after Bush briefed several members of Congress in the Cabinet Room, would provide a tax credit of up to $1,000 for each child under age 4 in low-income working families. He said 2.5 million American families would initially benefit from the legislation."Families would be free to choose the kind of child care that best suits their needs," Fitzwater told reporters during the daily news briefing.

Bush pledged during his presidential campaign that he would seek to assist low-income families, in which at least one parent works, by using the tax code to help defray the cost of child-care.

The legislation was being introduced on Capitol Hill by Senate Republican leader Bob Dole of Kansas.

"The important aspect of this program is that it encourages child care development," Fitzwater said. "It offers parents a choice that don't now have a choice - members of the poor . . . who cannot afford whatever programs are in their area."

"This offers federal assistance for parents that might want to use relatives for child care," he added, saying that "it gets at the problem from the standpoint of providing child care for those who do not currently have it available."

Under the bill Bush seeks, which will have to compete with Democratic-sponsored legislation, the tax credit would be provided to families with incomes ranging from $8,000 to $13,000 a year in the 1990 tax year.

For each child under the age of 4, families would receive a credit equal to 14 percent of wages, with a maximum credit equal to $1,000 per child.

The major Democratic bill is the $2.5 billion Act for Better Child Care Services. Most of the money would be for direct assistance to low-income families. The rest would go to improve quality, expand supply and set up an insurance risk pool. States would have to comply with minimum health and safety standards about five years after enactment.

Fitzwater noted that the child-care tax credit proposal was one of Bush's campaign pledges and said that it was "the substance or the basis of his meeting this morning with members of Congress who are interested in this proposal."

"Our purpose here is to provide . . . care where none exists," the spokesman said, "to provide maximum choice to families. Our belief is that parents can decide best how to take care of their children. So this maximizes options and it does not eliminate the more formal day-care centers and child-care centers."

Sen. Rudy Boschwitz, R-Minn., talking to reporters in the White House driveway following the meeting with Bush, said he thought the president was moving "in the right direction."

"The president is not using this program to set up a huge bureaucracy," Boschwitz said.

Under existing law, parents are allowed a $720 credit for child care costs incurred in order to accept or keep employment, but it applies only to families with sufficient income to pay federal income taxes.