Under the Town Planning Ordinance, no person shall undertake or continue a development in a development permission area (DPA) unless the development was in existence before the relevant interim development permission area or development permission area plans were gazetted, or the development is permitted under the relevant statutory plan, or permission from the TPB has been obtained. A development not satisfying these criteria is an 'unauthorised development' (UD) subject to enforcement and prosecution action. Currently, about 19 797 hectares of rural land have been designated as DPAs.

The Planning Authority may serve statutory notices on the respective landowners, occupiers and/or responsible persons, requiring them to discontinue an UD by a specified date or to reinstate the land. Non-compliance with a notice is a statutory offence.

In 2006, a total of 257 new UDs were detected in the rural areas. Most were related to uses such as open storage of vehicles, containers and construction machinery and related materials, car parks, container trailer parks, and workshops. The Director of Planning issued 2 574 warning letters and reminders for 470 cases, 1 248 enforcement notices for 197 cases, 152 reinstatement notices for 26 cases, six removal notices for two cases and 1 087 compliance notices for 178 cases. As for prosecution, 107 defendants in 36 cases were convicted. The average fine imposed was $12,285. Fines range from $1,000 to $91,900. During the year, enforcement action resulted in the discontinuation of 249 UDs covering 62 hectares of land, and regularisation of another 131 UDs covering 54 hectares of land through the planning application system.