The development of policies to support an agenda of urban rehabilitation as a part of a city’s approach to engender sustainability is a difficult process owing to the need to consider a large number of stakeholder needs and demands. For example, Hong Kong has accumulated a considerable amount of building stock due to its rapid economic development over the last 50 years. However, despite Hong Kong’s economic growth, it has overlooked the need to rehabilitate its existing building stock (i.e. to restore the condition, operation and capacity of buildings) As such, a significant proportion of Hong Kong’s aging building stock is in need of rehabilitation. Further, the absence of a systemic maintenance policy, has stymied the Hong Kong’s government’s ability to ensure that its private building stock are resilient and adaptable for the future. Responding to the resulting need to develop urban rehabilitation policies for Hong Kong, this paper develops a system dynamics (SD) model to: (1) understand the future trend of the aged private buildings, particularly their sizes and age distribution; and (2) examine the complex relationships between allocated resources such as building professionals, number of aged private buildings and the strength of rehabilitation policies. The SD model developed can be used as a planning tool to simulate the effects of regulatory changes on aged private building stock management in consideration of available resources. The model development relies on a real-life database that can be applied to any city that faces the need to rehabilitate its ageing building stock as a part of an urban rehabilitation strategy.