Whanganui District Health Board had the fifth-highest mortality rate in New Zealand in the 2010-11 year, according to figures released by the Ministry of Health.
The figures show 1.61 per cent of patients admitted to Wanganui Hospital died within 30 days of admission, a total of 156 people. This figure is the "standardised" rate that provides a fairer comparison than raw data.
WDHB's director of nursing and patient safety, Sandy Blake, said the DHB took mortality figures seriously.
"Chief executive Julie Patterson and I have put some important processes in place around when a patient dies," Mrs Blake said.
"We analyse the patient's notes and scrutinise the circumstances around their death to see if there's anything we need to be concerned about."