While one of the events involved the death of the patient, she said the cause of the death could not be definitively attributed to the adverse event.
Ms Yule said reporting such events helped the health board manage the risks of providing health care by identifying problems and failures in the system, so they could learn and prevent similar events from happening.
She said there had been a range of improvements including a reduction in falls programme, improved fluid balance charts, and improvements made for a safe and standardised clinical handover process across both hospitals.
Only one of the nine events happened at Taupo, with the rest happening in Rotorua.
Ms Yule said that, in the blood product case, the patient received fresh frozen plasma instead of platelets.
The blood was matched to the patient, so there were no compatibility issues, and the patient was not harmed as a result, she said. The health board would not give further information about the other cases, citing patient privacy.
Ms Yule said the reporting of events, in-depth investigations and development of programmes as a direct result of the events was positive.
"The process should give the Lakes DHB community confidence that we are transparent and open about serious adverse events and, equally, that we are willing to learn from the mistakes," she said.
Ms Yule said the health board had placed a strong focus on reducing the number of falls with harm.
It now aimed to have 90 per cent or more of high-risk patients assessed and given an individualised falls care plan.