Bird flu has been detected at an Australian egg farm, plunging it into lockdown amid fears it could be the strain causing mass poultry deaths across the world - and the possible cause of the next global pandemic.

Agriculture Victoria on Wednesday confirmed the presence of avian influenza after a number of poultry deaths at an egg farm near Meredith, about 40km north-west of Geelong.

The property has been placed into quarantine and Agriculture Victoria staff have arrived to support the business and investigate further.

Samples have been sent to the Australian Centre for Disease Preparedness at Geelong to determine the strain of the disease, Agriculture Victoria said.

Avian influenza is a highly contagious viral infection which can cause severe symptoms and sudden death in domestic poultry, wiping out entire populations.

A deadly strain, HPAI clade 2.3.4.4b, has been spreading globally, causing widespread outbreaks in bird populations and extensive deaths.

It has not yet been detected in Australia, the Department of Agriculture said.

The virus has also spread to mammals, including humans.

Infected people have observed mild symptoms or have been asymptomatic but some have experienced severe illness.

Bird flu could cause the next pandemic in humans, the US Centers for Disease Control has warned, as the H5N1 strain spreading on farms continued to mutate.

In a report published earlier this month, the agency said avian flu viruses 'have pandemic potential' in a section about rolling out vaccines if there is a human spillover.

A Texas dairy farm worker who caught bird flu from a cow suffered 'very mild' symptoms, but the virus caused blood vessels in his eyes to pop, leading to bleeding on the surface of his eyeballs.

The man is only the second person to be diagnosed with bird flu in the US, and the first globally thought to have caught the virus from a mammal.

Almost 900 people in 23 countries have been infected with the H5N1 strain of avian flu over the last two decades, but they were all linked to wild or domestic birds. 

Dr Vivien Dugan, who directs the CDC's flu division, insisted that the risk to the general public was still 'low'.

But she said repeated infections in cattle suggested the virus could become endemic in the species, raising the risk of an H5N1 spillover to humans, who have close contact with the animals.