1,000 rescue workers soldiers, police, medics, construction experts have been deployed to the site.

Rescue workers on Sunday picked through the rubble of a collapsed Chinese-owned building in a Cambodian beach town in a desperate search for survivors, after the construction site accident killed at least 18 people.

One person was pulled alive from the flattened seven-storey building late Saturday, more than 12 hours after it collapsed in the beach resort of Sihanoukville.

By Sunday morning rescuers had scoured barely half of the debris of twisted metal, glass and large concrete slabs.

The once sleepy fishing village has seen a Chinese construction boom buoyed by tourists to its dozens of casinos in recent years, with questions raised on the speed of development in a nation notorious for lax safety standards.

Three Chinese nationals and a Cambodian landowner have been held for questioning over the building collapse, which Cambodian Prime Minister Hun Sen blamed on "carelessness" by the construction company.

Rescuers pulled several bodies from the rubble late Saturday.

Relatives of the injured waited at nearby hospitals for news.

Rescuers had scoured barely half of the debris of twisted metal, glass and large concrete slabs.

It is not clear how many people were at the site at the time of the collapse.

At least 1,000 rescue workers, soldiers, police, medics and Chinese construction experts have been deployed to the site.

Some wore hard hats and oxygen tanks as they searched alongside several construction diggers, while the relatives of the injured waited at nearby hospitals for news.

Rescuers pulled several bodies from the rubble late Saturday, shooting the death toll up to 17, with 24 injured.

"We fear more bodies are trapped in the debris because the search has not reached the bottom of the building yet," the official told AFP, requesting anonymity.

It is not clear how many people were at the site at the time of the collapse, but a local official said earlier there would normally have been about 50 workers on the building site at the time.

A provincial official said "teams have searched about 40 percent of the debris", prompting concerns the toll will rise.

'Carelessness'

The southwestern town of Sihanoukville is awash with Chinese investment that has sparked a building frenzy to cater to mainland tourists flooding the town's city's casinos, beaches and glitzy hotels.

Beijing is pouring investment into Cambodia as part of its behemoth Belt and Road initiative, a sweeping trillion-dollar infrastructure programme across Asia, Africa and Europe.

Around $1 billion was invested in the Preah Sihanouk province between 2016 and 2018 alone, and there are around 50 Chinese-owned casinos and dozens of hotel complexes under construction in Sihanoukville.

Cambodia's prime minister said victims' families would be given $10,000 each.

"The tragedy of the building collapse in Preah Sihanouk province is painful... for our nation, especially the families of those who lost (their lives)," Hun Sen said.

Agence France-Presse