It comes as West Coast man Michael Saunders is facing charges over the death of his 2-year-old daughter, Emily, who was swept from the sport utility vehicle he was driving across a flooded river, and the death of Barry Petrie, 66, who died while trying to save her.
Last year Christchurch man Tula Ram Chhetri was charged and convicted of dangerous driving causing death over the crash which killed his wife, Mon Chhetri, and baby son, Aaron Chhetri.
He had been driving the family home to Christchurch, and pulled out in front of another car at an intersection.
Mr Imrie said he was not worried by the investigation, but just hoped it would be completed soon.
He said he had told police all he could, but said he had "blanked out" before the crash.
He said he was still struggling with the loss of his wife of 55 years, but was being supported by his family.