The Buildings Department said on Sunday that a No. 3 alarm blaze at Chinachem Tower in Central that sent four people to hospital over the weekend did not appear to have caused any major structural damage, and it's investigating whether any regulations were breached.

Scaffolding surrounding the building on Connaught Road Central had caught fire on Saturday, engulfing the structure in flames.

The department issued a statement on Sunday saying staff did not see any obvious structural hazards following an inspection of the site, but some loose materials on the exterior of the structure would need to be removed immediately.

It said the tower was undergoing minor works to its exterior walls and air-conditioning brackets, and the department had approved alteration works on some floors.

But officials stressed that all protective coverings, nets and tarpaulins used in scaffolding are required to meet strict flame-retardant standards, and an investigation is taking place to ascertain whether these materials were up to grade.

Officials warned that any violations of the Buildings Ordinance would be seriously addressed, including potential prosecution or disciplinary action.

As a safety precaution, all renovation works have been suspended for the time being, as workers begin clearing the damaged bamboo scaffolding, broken exterior glass and loose wall plaster.

"Due to emergency repairing works, all lanes of Pottinger Street between Des Voeux Road Central and Connaught Road Central are closed to all traffic," the Transport Department said.