UPDATED 02:37pm: There are concerns the front of a Hamilton house, severely damaged in a fire in which three people died, will collapse.

The bodies are still inside the two storey Collingwood Street house.

Waikato Fire Commander Roy Breeze says the house has been extensively damaged, so the priority is to make it safe.

He says urban search and rescue teams are shoring up the floor areas and staircase.

The blaze happened around five this morning, following a party at the place last night.

A student who didn't want to be identified says she was at the premises last night.

She says there was party there but she left before the fire started.

"All the ones that are accounted for are at the police station they're all fine. They're just a bit shaken up, hoping that everything's going to be all good but I think they know that a couple of people have passed away. Just not sure who it is yet."

Police and firefighters are trying to establish exactly how many people were in the building.

Police spokesman Andrew McAlley says the priority right now is to figure out exactly how many people were in the building.

"We already know that there has been more people accounted for from the building, both as casualties and people treated outside the fire than live at the property. That's why it's such a concern for police and fire."

Calls for compulsory smoke alarms

Fire Investigators say they need legislative help to get the message about smoke alarms across.

The recent death of three young people in a house fire in Hamilton has prompted fresh calls for compulsory smoke alarms.

Fire Investigation Manager Peter Wilding says there were no working smoke alarms in the house.

"Hardly a week goes by when someone's not badly injured or killed in a fire and we know we can stop that but we need legislative support to do that."