Bureaucratic red tape apparently has blocked, at least until the end of the month, federal funds to operate the Southern Maryland Head Start program. As a result, more than 300 children in the program had to stay home yesterday, according to Head Start administrators in Charles, Calvert and St. Mary's counties.

Jean Williams, director of the tricounty program said Head Start does not have the money to transport or feed the children enrolled in the pre-school enrichment program or to pay rent for the buildings it occupies.

She said no federal funds have been received since early September and the program has had to borrow money to meet its payroll for the last three weeks.

The reasons why the funds have been held up were not clear yesterday, despite numerous inquiries to officials at various levels of government.

"It sounds like a typical government snafu . . . its unfortunate, especially when children are involved," said one federal Head Start official, who asked not to be identified.

David Dukes, deputy assistant secretary of finance for the Department of Health, speculated that the funding problem may have been tied to the current debate over HEW's proposed 1978 fiscal budget.

According to Dukes, it is possible that the funds for the local program - even though they were part of the 1977 fiscal budget - could have been placed in a freeze after Sept. 30 when that budget expired.

Local officials, who say they were told that their funding package "may have been forgotten on someone's desk," have obtained the support of parents who have said they will ask their county governments to provide loans to support the Head Start program.

Yesterday, at the urging of a group of parents, the Calvert County government tentatively approved a $10,000 emergency loan to help the 81 centers in that county. Head Start officials say the money will enable them to open the Calvert County centers Thursday if there are no delays in the loan.

Parents in both St. Mary's and Charles counties plan to meet today to request emergency loans for their counties as well. If they are successful, local Head Start officials say they will be able to open the preschool centers in both counties by Monday.

Tricounty director Williams and other local Head Start officials said they have already borrowed all they can in an effort to make up for the $43,000 a month in federal aid that has failed to arrive.

When federal funds did not come through in September, the officials decided to ask the local Community Action Program for a $25,000 loan to meet payroll and other costs. That money soon ran out and the Head Start officials who still had not heard about their federal funding asked for another $10,000 from that same organization last Wednesday.

When they realized they were not going to receive their federal aid they immediately, met with their employees to inform them that they might not get paid.

Randy Smith educational coordinator for the Head Start program, said the employees at first agreed to work without pay, but later decided to shut down classes after they were informed of the uncertanity over when the federal funds would arrive.

Local officials said they were told only last week by the HEW regional office in Philadelphia, which controls the federal grant for their program, that their funding had been arranged in late September.

Leon Testa, a spokesman for Philadelphia office, said his office notified local officials last week that they would be receiving their money Oct. 30. He said he could not explain the delay and added that the final action for the grant takes place in the HEW accounting offices in Washington.

Local Head Start director Williams said, "We are told that the Federal Reserve Bank will be issuing a letter of authorization for $83,000 that will take effect Oct. 30" to cover aid that was due in October and most of September.

The program is available for children of low-and moderate-income families. A number of parents with children in the program said yesterday that its closure could impose large financial burdens on them because they will be forced to hire baby-sisters. A number also said Sead Start has had tremendous impact on their children by giving them education that is otherwise unavailable.