Paramedics were called to the sold-out festival at the Prince of Wales Showgrounds at about 4pm.

Ambulance Victoria spokesman John Mullen said a woman in her 20s was taken to Bendigo Hospital with possible spinal injuries.

She was in serious but stable condition.

St John Ambulance had treated six revellers by 1pm at its on-site tent.

Police with sniffer dogs had patrolled Southern Cross railway station to detect people travelling to the festival with drugs.

Senior Sgt Lionel Joseph said some police would travel back to Melbourne by train.

"Transit police will also be out in force at the end of the concert at Bendigo railway station and on return services to Melbourne for the safety of commuters," he said.

Revellers will rage into the night with Australian hip-hop artist Illy the headline act.