Hong Kong police have arrested nine employees of a company suspected of using surveying equipment with 45 forged certificates in five hospital expansion projects and a government construction site.

The force said on Thursday that it had apprehended six men and three women, aged 23 to 48, from acoustic and environmental services consultancy Novox for allegedly forging at least 45 certificates from four testing centres since 2022.

The surveying equipment was used to measure air quality, noise and vibration levels across the six projects, said Gar Kam-lam, superintendent of the force’s Kowloon West regional crime headquarters.

He added that police launched an investigation after receiving reports from several organisations alleging that a subcontractor had submitted falsified equipment documents.

“There is sufficient reason to believe the documents were produced by the company and its staff,” Gar said, noting that police had ruled out any involvement by the testing centres in the forgery.

Gar said that although officers also found authentic certificates during their search, police would continue investigating whether any other allegedly forged documents had been used in the company’s other projects.