Two companies involved in a concert by the popular boy band MIRROR in July last year were fined on Wednesday, after pleading guilty to violating occupational safety laws.

Two dancers were injured at the Hong Kong Coliseum on July 28 last year by a giant LED screen that fell from a height during the performance. Another dancer was hurt after falling off the stage during a rehearsal.

Studiodanz Company Limited and Engineering Impact Limited were among three firms labour authorities earlier initiated prosecutions against. It was alleged that they had breached ordinances related to occupational safety and employees' compensation.

Appearing at the Kowloon City Magistrates' Courts, Studiodanz Company admitted that it failed to ensure the safety of dancers, and take out insurance policies for them, and did not give notice of what had happened.

Engineering Impact, meanwhile, pleaded guilty to failing to ensure the safety of equipment at the venue, to give notice of the accidents, and to inform an occupational safety officer.

In sentencing, the court noted that both firms were first-time offenders, and fined Studiodanz HK$132,000, while ordering Engineering Impact to pay HK$220,000.

In a statement, the Labour Department warned that it spares no effort in prosecuting firms that violate the law.

"The [Labour Department] hopes that the judgment will send a strong message to other duty holders that they are required to protect employees' occupational safety and health, give notice of any accident to the Commissioner for Labour and take out employees' compensation insurance policies for their employees in accordance with the law," it said.

"The [Labour Department] safeguards [occupational safety and health] and statutory employment rights and benefits of all employees in Hong Kong."