"We'd like to express our condolences to the family. We're absolutely devastated by what's happened and we're also working to support our staff through this."
Hutton has owned River Rats for 21 years and the company has not had any fatal incidents in that time. The company is not operating in the short term while it works to support staff and help police and Maritime New Zealand with investigations.
The person's death will be referred to the Coroner and police inquiries are continuing.
Police could not make any further comments on the incident as inquiries were in the initial stages.
A blessing is believed to have taken place at the river this morning. A Maritime NZ spokesperson said staff had gone to the scene on Sunday and were investigating the incident.
An investigation typically includes further interviews and reviewing documents, at which point the information gathered is assessed and a decision made about what, if any, further action Maritime NZ takes.