Objective: To determine the sensitivity of the Interagency Integrated Triage Tool to identify severe and critical illness among adult patients with COVID‐19. Methods: A retrospective observational study conducted at Port Moresby General Hospital ED during a three‐month Delta surge. Results: Among 387 eligible patients with COVID‐19, 63 were diagnosed with severe or critical illness. Forty‐seven were allocated a high acuity triage category, equating to a sensitivity of 74.6% (95% CI 62.1–84.7) and a negative predictive value of 92.7% (95% CI 88.4–95.8). Conclusion: In a resource‐constrained context, the tool demonstrated reasonable sensitivity to detect severe and critical COVID‐19, comparable with its reported performance for other urgent conditions. [ABSTRACT FROM AUTHOR]