DoC Central North Island operations manager Damian Coutts would not say whether the department's investigation had finished.
It was an internal investigation commissioned under legal privilege, and as such its findings would not be made public, Coutts said.
As a result of the collision, DoC operations on the Whanganui River are subject to what the department calls "a stop". It started on April 23 and lasts for 90 days, but staff are still doing urgent work.
DoC was reviewing its work programme and working to reset its approach to health and safety across the district. The 23 staff in the Taumarunui, Pipiriki and Whanganui offices were very experienced, Coutts said.
A new layer of assessments and approvals were now required before field work could be undertaken by Whanganui staff.
Staff were continuing their work, based primarily in the Whanganui office, but the stop had meant the team's workload had been changed temporarily.
"This may mean some delays to some of the work."
He was confident this approach would allow the department to focus on ensuring its staff had the tools, skills and support they needed to safely complete their work.