The Environmental Protection Department (EPD) is stepping up efforts to tackle the growing problem of repeat offenders.
About one-third of 289 convictions under the Water Pollution Control Ordinance last year involved companies which had been before the court earlier.
Of the 444 convictions under the Noise Control Ordinance, two-thirds were repeat offenders.
It is possible some companies are factoring fines into their overall operating costs, while others are hoping the authorities will not catch them.
In some cases, the offences were committed due to a lack of awareness of environmental laws.
The EPD and the Local Control Offices (LCOs) will implement several measures to combat the problem. These include: securing higher fines for repeat offences; more frequent inspection and prosecution of repeat offenders; confronting the senior management of the companies concerned; providing guidance and technical advice to the offenders.