Authorities have warned against complacency following the first round of vaccinations against equine influenza (EI) on the eastern seaboard.

Racehorses in risk areas of NSW and Queensland received their initial shots over the weekend as did the first wave of those in training in EI-free Victoria.

Vaccination of potential Olympic equestrian competitors has also begun.

But Racing NSW chief steward Ray Murrihy said vigilance was more important than ever in the next two weeks until the first of the horses inoculated received their booster shots.

"Biosecurity is even more vital from here on in," Murrihy said.

"The last thing we want is for the whole thing to fall over.

"It is crucial that people get the message and continue to be vigilant."

The NSW central coast and Newcastle areas are among the main concerns.

Although racehorses at Gosford, Wyong and Newcastle's Broadmeadow track have received their first doses, anxiety is high.

Last week horses at Darren Smith's property at Williamtown, about 20km from Newcastle, were confirmed with EI.

"We want to keep ahead of it but it's only a question of time for it to get to Newcastle," Murrihy said.

"It's a race against time but hopefully the horses can build up some immunity before it gets there."

The EI outbreak has crippled the multi-million dollar racing and breeding industries in NSW and Queensland with the ban on horse movement all but ruling horses from the two states out of the rich Melbourne spring carnival.

Although Victoria does not have the disease, trainers have supported vaccination of their horses as a preventative measure.

The first case of EI in Australia was confirmed in a stallion at the Eastern Creek quarantine centre on August 23.

The horse had travelled from the northern hemisphere and was one of 43 internationally acclaimed stallions scheduled to stand in Australia and New Zealand this spring.

They were released from Eastern Creek last week but about half were returned to Europe or the United States as insurance against being stranded here if further outbreaks occurred.

An inquiry into how the virus escaped Eastern Creek and infiltrated the general horse population will begin in Sydney on Wednesday under the guidance of retired high court judge Ian Callinan.

There was good news in Queensland, with the all-clear given for horses at the Morgan Park equestrian centre at Warwick, south-west of Brisbane, to be moved from Tuesday.

The 250 horses and 100 people have been stranded for five weeks after horses there became the first in Queensland to contract EI.

The centre has been in lockdown while the virus made its way through the horses.

Under quarantine protocols, horses cannot be moved until the last horse contracts and recovers from the highly contagious disease.

A meeting in New Zealand on Tuesday of interested parties will discuss whether vaccination should be introduced across the Tasman.

New Zealand and Iceland are now the only countries in the world with large horse populations which have not recorded cases of EI.

However, with the constant movement of racehorses between Australia and New Zealand as well as from New Zealand to Asia, many trainers and breeders are calling for inoculation.

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