Production planning involves scheduling a series of operations in a factory to produce products on time. However, with the current increasing trend of customer demands for customisation where many variations are required, production scheduling is becoming increasingly difficult. High-mix low-volume (HMLV) manufacturing plays significant role to satisfy this trend since it has flexibility through automation to produce many different products in small quantities. Yet, such automated factories are prone to irregular events (e.g. line stoppages, machine breakdowns), making it a challenge to keep production activities on schedule. It is therefore important to consider irregular events as early as possible in the production planning stage to mitigate their impact. This paper proposes a delay prediction based on survival analysis to predict irregular events and calculate the disruptions so that they can be anticipated through the generation of robust production plans which can be executed at anytime. This approach can reduce production losses due to production delays caused by irregular events.