WASHINGTON: The US Department of Agriculture is trying to re-hire several employees it accidentally fired at the weekend who were working on the response to bird flu, local media reported.

"Although several positions supporting (bird flu efforts) were notified of their terminations over the weekend, we are working to swiftly rectify the situation and rescind those letters," a USDA spokesperson told NBC News.

"USDA's Food Safety and Inspection Service frontline positions are considered public safety positions, and we are continuing to hire the workforce necessary to ensure the safety and adequate supply of food to fulfil our statutory mission."

United States President Donald Trump has sought to slash the number of federal employees, a task masterminded by billionaire Elon Musk and his government efficiency group.

However, the cuts come after a new strain of "highly pathogenic avian influenza (HPAI) H5N9" was confirmed at a duck farm in California last month, the first time the bird flu variant has been found in poultry in the US.

The USDA spokesperson said several agency positions - including veterinarians, animal health technicians and emergency health personnel - had been exempted from Trump's cuts in order "to continue to support the HPAI (bird flu) response".

The Agriculture Department "continues to prioritise the response to highly pathogenic avian influenza", they said.

Politico reported that 25 per cent of the staff were fired over the weekend across 58 facilities responding to the spread of bird flu, and that thousands of USDA employees were notified they would lose their jobs.

The USDA did not respond immediately to AFP's request for comment.

The Trump administration sacked nearly half of an elite US epidemiology program known as the "disease detectives" last week, dealing a blow to public health efforts.