Plastic packaging wastes are increasing due to the COVID-19 pandemic as consumers tend to stay home and purchase online. Plastic packaging waste is difficult to break down. It pollutes the environment and then enters the food chain, putting people and wildlife at risk. This paper presents the development of system dynamic models for sustainable plastic supply chain management in Klang Valley, Malaysia. System dynamic models for plastic supply chains, including forward, open-loop and closed-loop supply chains, were developed using Vensim 7.2 PLE software. To estimate the amount of plastic packaging wastes discharged at landfill, these models were simulated using various waste diversion rates. The results indicated that, when all stakeholders in the supply chain recycled 10% of their plastic packaging waste, the total amount of plastic packaging waste going to landfill could be reduced by approximately 65%. However, the means of open-loop and closed-loop supply chains, did not differ much.