The Mirror concert on July 28 was cut short after a large LED screen suspended above the stage fell onto a group of performers, hitting one in the neck and leaving him in critical condition.

Police said this afternoon that the five people arrested early on Friday were senior employees of main stage contractor Engineering Impact and subcontractor Hip Hing Loong Stage Engineering Company.

Three men and one woman from Engineering Impact and one man from Hip Hing Loong Stage Engineering Company, aged 40 to 63, were arrested on suspicion of fraud and a charge of allowing an object to fall from height, and were currently detained at the Hung Hom Police Station for investigation.

The force said Engineering Impact has made false declarations about the weight of its stage equipment when filing the performance application to the Leisure and Cultural Services Department.

The police spokesman said the most severe underreporting centred on eight sets of speakers on the stage, with the sets weighed 12,240 pounds (5,552kg) – seven times more than the contractor’s reported weight of 1,600 pounds.

Investigators believed the error was intentional to mislead authorities in expediting the clearance for the performance.

“There were lots of factors that caused the accident, and the numerous underreported weights could just be one of the causes,” the spokesman added.

Police also said surveillance footage in the stadium on the morning of July 28, hours before the accident, showed subcontractor Hip Hing Loong had spotted problems with the LED screen that later fell onto the stage, but did not make any major corrections.

Police noted that the arrests made today did not signal the end of their enforcement actions and will not rule out the possibility of further arrests.

Meanwhile, a government task force set up to investigate the incident was said to release the incident report this afternoon at the earliest.

The task force said in August that a substandard cable was used and that the screen's weight was under-reported -- though at the time it did not say who should be held responsible.

Dancer Mo Li, who recently turned 28, is still hospitalized following the incident and suffered a severe spinal injury. He was in critical condition for more than a month, with doctors saying chances of full recovery were slim.

Last month, concert organizers Music Nation and MakerVille defended their choice of production crew and rejected accusations of cutting corners.

"We chose to hire teams that are considered top-notch in the industry... Cost is not our primary consideration," they said in a statement.

Hong Kong generally has good safety standards but a spate of recent deadly workplace accidents have heightened concerns that not enough is being done to protect workers or punish employers when avoidable accidents occur.

In September, three men were killed and six others injured after a crane collapsed at a construction site.