The Housing Bureau has ordered a halt to a maintenance project in Sham Shui Po after inspectors discovered that plastic sheeting had been used to cover the windows at the Yee Kok Court housing estate.

In a statement, the bureau said the registered contractor of the project has been asked to remove the plastic sheeting immediately, and it's seeking legal advice on whether to prosecute.

The bureau's Independent Checking Unit had ordered the work to be suspended "for the sake of prudence", and the contractor has been asked to conduct an independent safety audit to review their safety management system.

Only after an improvement plan is submitted and improvement measures are taken would authorities consider allowing works to resume, the Housing Bureau said.

Similar measures have been taken at two other buildings in North Point and Central where windows were earlier found to also be covered by plastic sheeting.

Authorities have pointed to the extensive use of highly flammable polystyrene foam boards to cover windows at Wang Fuk Court as having contributed to the rapid spread of the fire at the Tai Po estate.

The Buildings Department has said the deadly blaze had exposed "serious deficiencies" in site safety management on the part of the registered contractor of the works at Wang Fuk Court – Prestige Construction & Engineering Company (PC&E).

It had earlier suspended works on 28 projects managed by PC&E over concerns about its ability to ensure site safety.

The deadly fire – which has claimed at least 146 lives – had prompted territory-wide inspections of buildings undergoing external wall maintenance.

As of Sunday, 319 such buildings have been inspected, and for those that use scaffold nets, samples have been taken for testing.

No other buildings were found to have used foam boards or plastic sheeting to block windows.

In a related operation, the Labour Department has inspected 51 construction sites to check fire protection measures and emergency preparedness at buildings undergoing maintenance work.

As of Sunday, the department has inspected 51 construction sites, issued a total of 45 written warnings and 12 improvement notices, and has taken out two prosecutions.