Police are waiting for a 21-year-old man found dumped outside Tauranga Hospital with serious injuries to undergo surgery before speaking to him.

Police were unsure how the man was injured but it appeared he had been assaulted, Senior Sergeant Carl Purcell of Tauranga said today.

He was found dumped outside Tauranga Hospital where he was admitted to the emergency department about 1am yesterday with a skull fracture, broken arm and facial lacerations.

He was transferred to Waikato Hospital where he was undergoing surgery today, Mr Purcell told NZPA.

Police planned to speak with him after the surgery to establish how he was injured.

Police want to hear from anyone with information.