Media personality Mike Puru is in hospital with a broken rib and concussion after crashing his bike in Auckland.

Puru, who co-hosts NZME's radio show The Hits with Stacey Morrison, said he doesn't remember anything after leaving work on Thursday evening.

"When I woke up on Friday morning I was in hospital - apparently I was found unconscious next to my bike. Some passersby stopped and called an ambulance for me."

St John took him to Auckland Hospital, stopping off at his house to drop off his bike.

His mother Diana Puru posted to Facebook that she was looking at flying to Auckland after the crash.

"OMG our Mike has had an accident on his bike Has a fractured rib and punctured lung Im so worried Looking at flying up," she wrote.

Puru said he in fact had air around his lung, as well as a concussion and a broken rib.

He doesn't know where he was found but his usual route takes him up Nelson St and along the pink cycleway, to Great North Rd and Grey Lynn.

"I'm pretty sure I crashed on my own - there were no police involved or anything. I've tried to piece together some missing bits but I'll probably have to talk to the ambulance staff," he said.

"My partner and his friend came to hospital and apparently were here till 2 or 3 in the morning. They were just concerned I might have a head injury and bleeding on the brain but luckily the second scan showed I was ok."

Puru is still in Auckland Hospital but hopes to be discharged this afternoon. Hospital staff had been "awesome" and he had good roommates, he said. He was also grateful to the people who stopped to help.

Puru had been wearing a helmet which he believed saved him from facial injuries, as he escaped with just an abraded lip.

"My head hurts and my helmet's been pretty much munted - thank God I was wearing a helmet."

And he has a message for other bike riders: "Always wear a helmet". It could save your life.