ABSTRACTThis study aimed to understand nurses' perceptions of COVID‐19‐related policies and risks during the outbreak of COVID‐19 in Hong Kong and to determine how their perceptions influenced their mental health status. A web‐based online survey among Hong Kong nurses was conducted. The questionnaire included a self‐designed 5‐point Likert scale with 17 items to assess the nurses' perceptions of COVID‐19‐related policies and risks, as well as the Davidson Trauma Scale (DTS), the Perceived Stress Scale (PSS), the Patient Health Questionnaire‐2 (PHQ‐2) and the Generalised Anxiety Disorder scale (GAD) for measurement of posttraumatic stress disorder (PTSD), stress, depression and anxiety, respectively. Of 592 nurses enrolled, 30.6% had PTSD (DTS total score ≥40), and 80.4%, 19.9% and 16.4% had moderate‐to‐high levels of stress (PSS‐10 score ≥14), depression (PHQ‐2 score ≥3) and anxiety (GAD score ≥3), respectively. The top three concerned aspects were ‘worried about themselves and friends to suffer this disease’ (84.5%), ‘insufficient number of isolation wards’ (81.8%) and ‘insufficient number of personal protective equipment’ (74.3%). Logistic regression analyses showed that more negative perception on ‘personal protective equipment in the healthcare institutions’, ‘the confidence in HK's control of COVID‐19’, ‘worried about themselves and friends to suffer this disease’ and ‘self‐perceived risk of infection’ indicated higher severity of the four mental health problems (all p < 0.01). The perception on ‘public gathering ban’, ‘the number of isolation wards’ and ‘expected time to control COVID‐19’ were significantly associated with PTSD and stress (all p < 0.05). Nurses' perception on government policies and COVID‐19 risks played an important role in predicting their mental health status. Policy makers should be aware of nurses' psychological responses and provide timely and targeted emotional support to nurses amid and after the COVID‐19 pandemic.