Secretary for Housing Winnie Ho said on Monday construction violations at three light public housing projects under the same contractor is an "isolated case" and that the government will make sure completed projects are of high quality and safety standards.

This came after the Architectural Services Department issued a statement, saying it had established an independent investigation team after finding more on-site installation issues at projects located in Siu Lam, Tuen Mun and Chai Wan, which are all under the contractor Able and Chun Wo Joint Venture.

The contractor was first found to have taken construction short cuts in August, with screws found to have been shortened without approval.

Subsequent probes then discovered that holes connecting different metal boards of construction components had expanded.

Speaking after a Legislative Council housing panel hearing, the director of the Architectural Services Department, Michael Li, said the holes came to light after follow-up action taken in September.

About 6 percent of screws had been shortened in these projects, while expanded holes make up 20 percent of 2,000 metal boards checked, he said.

"We will continue to investigate and collect evidence to determine whether related personnel or companies have to bear responsibility," Li said.

"At the same time... we will ensure light public housing projects will be completed in a timely fashion with high quality and safety standards.

"I have assigned a deputy director to lead the independent investigation team, in order to find out the reasons, provide improvement plans, and sort out liability issues," he added.

Li said his department is currently reviewing a repair plan submitted by the contractor, which would take around four to five months to carry out.

He also hoped to submit the investigation report to the Housing and Development bureaus within a month.

Ho said light public housing projects that had already been completed are of high quality, citing the lack of quality issues over the past few months amid strong typhoons and heavy rain.

"In the past we have already finished a lot of light public housing projects, and the about 4,000 units were given out for residents to live in," she said.

"For example, the light public housing project at Choi Hing Road experienced a few typhoons, one of which was a strong one, along with Black Rain conditions, showing the components were of very high quality."

She added that the department has a very proactive and comprehensive system when it comes to inspecting construction works.

"The department proactively discovered the problem, proactively carried out comprehensive checks, took out all the problems and have the contractor to deal with it. Therefore, we are very confident on the quality of light public housing projects," Ho said.

The minister added that the department will make sure all projects are safe and of high quality before handing out to residents.