Regulations set for release today will expand by tens of thousands the number of poor children entitled to disability benefits each year, administration officials said yesterday.

The Health and Human Services Department regulations were ordered nearly a year ago by the Supreme Court after advocates for the rights of the disabled complained that the administration had delayed in crafting them.

Under the new rules, effective immediately, the government in allocating benefits will for the first time consider not only children's medical conditions but also the effect those conditions have on their ability to walk, eat, dress themselves and perform other daily activities.

The change is expected to add yearly to the Supplemental Security Income program as many as 37,000 children with severe physical and mental disabilities who would not previously have qualified for benefits, at an estimated cost of $2.5 billion to $3.5 billion over the next five years.

"These new rules greatly enhance the protections we can provide to some of our most vulnerable citizens -- children with disabilities," Secretary of Health and Human Services Louis W. Sullivan said in a statement.

About 312,000 needy, disabled children now receive SSI benefits, which average $387 per month. About half of all applicants now qualify, but the administration expects as many as 65 percent of those applying to qualify under the new plan.

By a 7 to 2 vote, the Supreme Court last year voided a government regulation that gave children seeking benefits less protection than adults. The old rule applied a rigid list of disorders to children but permitted adults to be judged on their ability to work. Advocacy groups complained the list did not account for the cumulative effect of disabilities on children's daily lives.