The Agriculture Department has agreed to permit the sale of more than 30 million pounds of Australian beef suspected of illegal pesticide residues, provided the Australian government conducts additional tests to assure that the meat complies with U.S. health standards.

The agreement, announced yesterday by the department's Food Safety and Inspection Service, reverses a week-old ban on $50 million worth of Australian beef shipments that was imposed after federal inspectors found the meat contained impermissibly high levels of DDT, dieldrin and other pesticides.

"Australian authorities understand the seriousness of this problem and intend to take whatever action necessary to be sure that beef shipped to the United States will be wholesome," Agriculture Secretary Richard E. Lyng said.

Officials announced last Thursday that the department was suspending inspections of Australian beef processed before May 25, when Australian officials tightened their testing procedures in response to U.S. complaints about pesticide violations. Inspectors have found eight pesticide violations in meat processed before that date, the most recent discovered earlier this month.

The action amounted to a ban, because the meat cannot enter the U.S. market without the inspection.

A spokesman for the food safety service said yesterday that the department will resume inspections of beef from 24 Australian packing plants "where we have data to show little likelihood of residue violations." However, beef from 41 other Australian plants will require additional sampling and testing, at Australia's expense, before it will be eligible for U.S. inspection, she said.

The 41 suspect plants account for about 70 percent of the beef being held in warehouses, the department said.

Australia, the largest foreign supplier of beef to the United States, shipped 678 million pounds to the United States last year, representing 29 percent of the nation's meat imports. The U.S. action to restrict some sales brought a high-level delegation of Australian officials to Washington this week to discuss the problem with Lyng.

John Kerin, Lyng's Australian counterpart, said in a statement released by the Australian Embassy here that he was pleased with the agreement and hoped it would erase the uncertainties that have hampered Australian beef marketing in recent days.

Tim Mackey, agricultural counselor at the embassy, said earlier this week that Australian inspectors found pesticide violations in a "small proportion" of beef exports, based on a "very much higher sampling rate . . . than is conducted in the U.S."