BACKGROUND: The coronavirus disease 19 (COVID-19) has led to increased reliance on the internet. How problematic usage of the internet (PUI) and COVID-19 related stress and other clinical variables relate, is unknown. We hypothesised that higher PUI level would be significantly associated with higher levels of: (i) pandemic-related stress; and (ii) impulsive and compulsive symptoms and traits. METHODS: An online community-based cross-sectional survey was used for data collection. Relationships between PUI level and other variables were characterised using correlational analyses. Regression analyses determined the cumulative explanatory power of variables, with partial least squares structural equation modelling (PLS-SEM) to explore path loadings. ANOVA was used to investigate PUI level at varying lockdown levels. RESULTS: Data from 2110 participants (64.5% female), aged 18-64 years (mean: 24.3, SD: 8.1) suggested that approximately a quarter (n = 489, 23.2%) had medium to high level internet use problems. Impulsive and compulsive symptoms and traits, pandemic-stress, and age were all significantly related to PUI (p < 0.01). These associations (medium effect sizes) cumulatively explained 29% of PUI variance. PLS-SEM indicated significant contributory effects, with the association between age and PUI level mediated by impulsivity, pandemic-stress and compulsivity. DISCUSSION: Pandemic-stress, impulsive-compulsive symptoms and traits and age were related to PUI level. Enhancing resilience to stress, particularly in vulnerable populations, through lifestyle changes and implementation of adaptive coping strategies, is key to reduce risk for PUI during the COVID-19 pandemic and beyond.