Background The COVID-19 pandemic has had a disruptive effect on people with haematological cancers, who represent a high-risk population due to the nature of their disease and immunosuppressive treatments. We aimed to identify the psychological impacts of the COVID-19 pandemic on haematology patients and identify correlated factors to inform the development of appropriate supportive interventions. Methods Three hundred and ninety-four respondents volunteered their participation in response to a study advertisement distributed online through established haematology groups. Participants completed a self-report online survey exploring wellbeing, psychological distress, unmet supportive care needs, and fear of cancer recurrence. Results At least 1 in 3 respondents (35%) reported clinical levels of distress and nearly 1 in 3 (32%) identified at least one unmet need. Among respondents in remission (n = 134), clinical fear of cancer recurrence was reported by nearly all (95%). Unmet needs, pre-existing health conditions, younger age, financial concerns, and perceived risk of contracting COVID-19 were the dominant factors contributing to psychological distress during the pandemic. Psychological distress, lost income, perceived inadequate support from care team, perceived risk of contracting COVID-19, and being a woman were significantly associated with unmet needs. Psychological distress and concern about the impact of COVID-19 on cancer management were significantly associated with fear of cancer recurrence among respondents in remission. Conclusion Results highlight the high psychological burden and unmet needs experienced by people with haematological cancers during the COVID-19 pandemic and indicate a need for innovative solutions to rapidly identify distress and unmet needs during, and beyond, pandemic times.