Six injured workers were taken to the hospital soon after the accident, but one man remained trapped in the wreckage.
“We can only see the lower half of his body, and he was unresponsive when we tried to communicate with him,” Yim said.
“(The crane) is quite heavy so we need various tools and risk assessment before we can rescue the trapped worker.”
After inspecting the site, Secretary for Labour and Welfare Chris Sun told reporters there was a clear problem with the crane’s base and ordered work to be suspended at the site.
Hong Kong leader John Lee said the labour department would investigate the incident and inspect construction sites using cranes to ensure they complied with safety standards.
Lawmaker Kwok Wai-keung, who represents the labour sector in Hong Kong, said crane collapses are rare in the city and called the accident a “major blow” to the industry.
The crane was installed in August and had been in use before Wednesday’s accident, authorities said.
The scene of the accident was part of a massive construction site for a subsidised public housing project that aimed to create 19,000 homes, the South China Morning Post reported.