His pained, bloodied and dirt-streaked face has become one of the defining human images of the Christchurch quake and has been published in media across the globe.

But Shane Tomlin's family still have no idea where he is, or if he is even alive. Mr Tomlin, 42, was pulled from the wreckage of the Trocadero Bakery in Cashel Mall after the quake.

With one rescuer cradling his head, the injured man moaned in pain as he was lifted out of the destroyed building.

His mother, Doreen Tomlin, told the Herald there had been no sign of her son since. "The floor opened up and he fell right through to the next floor. I think he injured his back, but from the photo, it didn't look like he was going to die," she said.

"They took him to hospital on top of a police car. There were no ambulances around so a policeman came over in his car and they lay Shane on top of it. There was a joker on each side holding on to him and they took him in like that."

Mrs Tomlin said a social worker at Christchurch Hospital spent most of Wednesday looking at unnamed and unidentified victims to see if she could spot him, but had no luck.

There is no record of his name at the hospital and the person who dropped him off there has not heard from him either.

"I think that he's in the hospital, but is too sick to make a phone call. He wouldn't have any ID on him so people won't be able to tell who he is," Mrs Tomlin said.

"I think that we might hear something in the morning ... We definitely still have hope."

She said the extensive media coverage should cause someone to come forward with information on his whereabouts. She also said it was eerie seeing the image of her son, moaning and groaning in pain.

"I picked up the paper the next day and he was on the front page, and then we were sitting in the lounge and my daughter said, 'Look, he's on television', and it was the BBC news.

"They've all got that image, but we can't find him," she said.

His sister Karen Franicevic said on Campbell Live: "Just the idea that he's in a hospital somewhere by himself. That he doesn't know that we're looking for him. And quite possibly lonely, I don't know. But he's on his own somewhere, after as you can imagine he would have been quite afraid and terrified. And we just want him to know that we want to be with him."