Only two people have been charged for driving while impaired by drugs since police started drug testing on November 1.
And as at December 9, 36 impairment tests had been carried out throughout the country, figures released to the Herald under the Official Information Act show.
But national road policing manager Superintendent Paula Rose said the figure on the number of prosecutions was provisional, as police were awaiting results from blood tests done on others of the 36 drivers.
The drug-driving provisions of the Land Transport Amendment Act 2009 gave police greater powers to deal with people driving under the influence.
If officers suspect a person is impaired by drugs they can carry out an initial test.
That involves them looking at a person's pupil size, reaction to light, lack of convergence and abnormal eye movement. The person will also be required to do a walk-and-turn assessment and stand on one leg.
If the driver does not satisfactorily complete the test, the police officer may forbid them to drive, and require a blood sample.
Ms Rose said more than 500 staff had been trained to carry out the tests.
However, if a non-trained officer suspects a motorist is impaired by drugs they can call on a trained officer.
Depending on how many offences a driver commits, they can face up to two years' jail, a fine of up to $60,000 and disqualification from driving.
If injury or death is caused while the motorist is affected by drugs, they can face up to three years in prison or a fine of up to $10,000.
The amendment act also made it illegal for motorists to use cellphones while driving. In the first month of the new law, 262 drivers got tickets.
The highest number (60) were issued in Auckland City, followed by Waitemata (45) and Wellington (33).
The law also required motorcyclists to use headlights during daylight hours. As at December 3, five riders had been given tickets for not doing so.
