Online photos showed part of the concrete ceiling - about half the length of a fluorescent tube - were missing in the Jordan hospital's male staff changing room, and a rusted bar was exposed.

A hospital spokesman said potential hazards in the changing room were found when in-house engineers conducted a full inspection in all buildings on Wednesday, prompted by three recent ceiling collapses..

Sources said the team found cracks in the ceiling and sealed off the area for follow-up action.

"Repair works have been immediately arranged. Online photos showed the ceiling during maintenance, when the concrete covering had been chiseled for repair work," a spokesman said.

"The area is not for clinical use. After preliminary assessment, the engineering department believed the structure is safe.

"But as prudent measure, the engineering department has cordoned off the area so hospital staff would not pass through it. Repair works will be completed in a day or two."

The spokesman said the area will only be reopened after engineers confirm everything is fine.

"The hospital takes facility safety as top priority. It will step up surveillance and supervision of contractors' maintenance and repair works to ensure a safe environment," he said.

The ceiling with cracked concrete was found on the first floor of a two-story building used as a staff changing room. The first floor serves males and second floor females.

In the early hours of Wednesday, at least five concrete slabs fell from the ceiling and crushed a computer and a printer on a table in a consultation room in a pediatric and teen psychiatric ward at Kwai Chung Hospital.

It was the third ceiling collapse in public hospitals revealed in less than a week.

Also revealed on Wednesday was a mishap in a male toilet in Tuen Mun Hospital, when a down ceiling panel fell.

In November last year, an A4-sized concrete chunk fell on a vacant bed in Castle peak Hospital.

No one was injured in the mishaps.

Maintenance and repair work at all 43 public hospitals are conducted by Fujitac Construction & Engineering Consultants, whose contract with the authority expires in November.

The company said it is highly concerned about the mishaps and it will assist a six-strong review committee formed by the HA for follow up action.

Medical and healthcare lawmaker David Lam Tzit-yuen urged the authority to speed up repair and maintenance at public hospitals, as half of them were built more than 30 years ago.

Speaking on a radio program yesterday, Lam said the authority awards tenders to a company offering the lowest price. "The HA must strengthen vetting of contractors," he said.