The motorist had dropped the footage off at an Auckland police station, from where it would be forwarded to the investigation team.
Both women, who police said appeared to be in their 80s, died at the scene.
The single occupant of the other car, an Auckland man in his early 30s, was also badly injured.
He was taken to Waikato Hospital where he was in a stable condition, a hospital spokeswoman said.
Mr Tooman said while the dead women were yet to be formally identified they were believed to be locals and not overseas visitors.
"It appears today's tragedy was a case of driver inattention. With an anticipated increase in traffic flows over the next few weeks we want to reiterate the importance of keeping to the left at all times."
Road toll down for year
Ministry of Transport figures released earlier today place the number of road deaths for the year to date at 193, which is 66 fewer than this time last year.
There have been 179 fatal crashes this year, compared to 233 to date last year.
Fatalities over the last three years have steadily decreased, dropping from 278 on this day in 2009.
Records show drivers are the most common casualty type this year, and pedal cyclists the least.
The trend follows a 30-year low in May this year, when the road toll was the lowest recorded for that month since transport authorities began keeping annual figures in 1980.