BALTIMORE -- Maryland social service officials have refused to enforce new federal rules requiring cuts in welfare payments to recipients who receive outside help paying rent, calling the regulation ridiculous.

"This simply flies in the face of our efforts to help poor people find ways to stretch their resources," said Ernestine Jones, deputy secretary of the Maryland Department of Human Resources. "We frankly think this is ridiculous."

The Reagan administration has decided that welfare recipients who get money from someone else to help pay rent, such as a recipient sharing rent with another person, should have their benefit checks reduced by the same amount.

Maryland officials cited an example in which a recipient studying to be a computer technician was struggling to make ends meet while caring for her family on a monthly payment of $359. She was sharing a house with another family, and the government would have cut her payment as a result.

State officials say they think the policy is nonsensical because it would apply only to tenants who use cash to pay their rent and then only to one of two tenants involved.

Administrators at the U.S. Department of Health and Human Services declined to comment on the policy. But a spokeswoman said officials were trying to enforce existing rules covering "unearned income."

"Apparently, they're assuming that if someone is getting cash, it could be spent on something besides the rent," said the spokeswoman, Carol de los Reyes.

Under the rule, for example, one mother on welfare who pays another welfare mother $200 a month for half of the $400-per-month apartment they share would have her benefits cut by $200.

In Maryland, as many as 33,000 welfare families are thought to be involved in house-sharing.

Maryland is challenging the policy in writing to federal officials of the Aid to Families with Dependent Children program, which is jointly funded by the state and federal governments, she said.

Jones said she and other human resources officials are prepared to go to court to contest the policy.