​The Buildings Department says there was "no obvious danger" to the overall structure of a residential building after a deadly fire in which five people were killed.

The department said it's cooperating with the Fire Services Department investigation into the blaze.

The fire broke out on Wednesday morning at a gym in New Lucky House on Nathan Road in Jordan, and authorities said they had communicated their concerns about fire prevention work to the owners' corporation in the past.

In a statement issued early on Thursday, the Buildings Department said a registered inspector had submitted a report in May last year, recommending repair works, including the replacement of fire doors, the provision of protected lobbies for an escape staircase and other work required by law.

The department said it would follow the matter up with the owners' corporation to urge it to start repair works as soon as possible, and would consider enforcement action if necessary.

It said it had issued a directive to the owners' corporation in 2008, calling on it to upgrade some fire safety provisions to meet current standards. But while the corporation appointed a consultant, it had still not complied with the department's directive.

The department said it had received seven reports of subdivided flats in the past three years. It said five of those cases did not involve unauthorised building works. The other two cases did, but were not on the first and second floors where the fire took hold.

It said it ordered the owners of the premises to reinstate fire resisting doors at the main entrance of the premises and the premises' fire compartment wall.