Major concerns that ongoing staff shortages at Nelson Hospital are putting patients at risk

The Association of Salaried Medical Specialists claims an email was sent to clinicians today, advising the hospital would be without a medical registrar until 10pm.

Executive Director Sarah Dalton says the hospital's relied on minimal staffing levels for years.

She says it's not investing in safe staffing, meaning patients and workers rostered on, pay the cost.

Dalton says they held a crisis meeting with Health NZ's deputy chief executive in January - but nothing's been done.