Labour Secretary Chris Sun on Thursday said authorities will inspect all enclosed construction spaces in the territory within the next two weeks, after the death at the weekend of two men working underground in West Kowloon.

The pair were replacing pipes of the Elements mall when they suffered apparent gas poisoning.

Speaking on Commercial Radio, Sun said officials would look into the responsibilities of every contractor as they investigate the incident.

"In cases of industrial accidents, we don't just pursue the frontline contractor but also the main contractor. Of course we have to see their respective level of responsibility," he said.

Asked if the MTR Corporation, which owns the shopping mall, has any responsibility, Sun said past experience shows it is usually the contractors that are at fault.

"For incidents of serious negligence like this, we'd discuss with the Department of Justice once we have gathered evidence and would seriously consider handling the case under the latest regulation, which carries a maximum penalty of a HK$10 million fine and two years in prison," he said.

Meanwhile, the chief executive of the Association for the Rights of Industrial Accident Victims told RTHK that the administration should require contractors to declare all projects involving confined spaces, and not just works of a longer duration or involving a large number of workers.

"The Labour Department would have more information for conducting inspections. And even if they don't inspect the site, the contractors will be vigilant because they would expect to be inspected anytime," Siu Sin-man said.

However, the Construction Sub-Contractors Association president Lawrence Ng said it would be difficult to notify the authorities of such projects in advance, since there are over a thousand construction sites across the city at any one time.