Nowadays, Australian state and local governments consider Green Infrastructure (GI) planning as a mitigation and adaptation approach to make cities more resilient. Moreover, decision-makers have acknowledged and addressed social values, biodiversity, and habitat connectivity in policy documents. Canberra in the Australian Capital Territory (ACT), is a unique Australian city since it is totally designed as the National Capital of Australia and is built on a grassland plain, inspired by the Garden City concept. The green and open spaces have a symbolic value, representing Canberra as the national capital. However, Canberra is experiencing increasing urban development pressure, which threatens its green and open spaces. Thus, it is critical to explore the GI status in governance and decision-making in Canberra to guide its future planning. This research explores ten policy documents using a reflexive analysis to interpretatively critique policy documents and to diagnose the existing opportunities and constraints in Canberra’s GI planning. The documents were selected from 4 main defined scopes, Australian Government land-use responsibilities, ACT Government land-use planning and strategy, ACT Government greenspace planning, and Tree management regulations and mechanisms. This research identified dual governance (national/territory) and dual nature character (native/exotic) in the policy documents, which has intensified the complexity of GI planning. Another constraint was the lack of district level planning and a structured bottom-up approach. More flexibility in governance and collaboration between different governance levels and agencies is needed to make a more effective GI network, using the existing opportunities such as open space systems. Although GI principles have been addressed at Canberra’s strategic level, more comprehensive GI planning is needed to address all types of greenspaces.