The men who found him administered first aid and called St John.
"If it hadn't had been for those guys finding him when they did, the situation could have been a lot more serious,'' Scoles said.
A St John spokesman said an ambulance arrived about 3.30am. Staff found the man bleeding from his head.
The victim had been conscious when he was taken by ambulance to the Dunedin Hospital emergency department, he said.
Scoles said the injured policeman was in a serious but stable condition yesterday.
A police investigation had revealed no suspicious circumstances, he said.
The man's family arrived in Dunedin yesterday, he said.
"The news was positive around recovery - the length of time of the recovery will be the issue.''
Australian Police Rugby Union officials had remained in Dunedin and "are in a pretty bad way - they are worried about him''.
Australian Police XV players and remaining union management left for Queenstown for the game against New Zealand Police today.
"It's an extremely tough time for players and management of the Australian Police Rugby Union team,'' Scoles said.