Nick Bryant BBC News, Sydney

Horses in Sydney have been confined to their stables

The government of New South Wales in Australia has extended indefinitely its ban on the movement of horses around the state.

It has also extended indefinitely the cessation of race meetings.

More than 400 horses are now showing symptoms of the highly contagious equine influenza virus.

Officials are clearly struggling to contain the disease, which has now spread in New South Wales and over the state border into Queensland.

For the first time, racehorses might also have been infected. Three thoroughbreds have shown symptoms at the Randwick race course in Sydney where 700 horses are trained.

Economic woes

Those caught transporting the animals could face up to a year in prison.

The police say they have already stopped and spoken to more than a hundred people since the lock-down started on Saturday.

With its meetings cancelled, the multi-billion dollar racing industry is being hit hard, as are horse breeders whose season is due to start on 1 September.

The country's treasurer, Peter Costello, warned the shut-down would affect the Australian economy.