The serious crash unit is investigating two separate fatal quad bike accidents on Saturday.
One person was killed on a rural property in the Manawatu, and another in Okiwi Bay in Nelson.
Farm safety director D'Arcy Palmer stresses the importance of sticking to safety rules.
"It's not hard at the end of the day, but farmers - we're in a hurry, they're such a wonderful machine - but like anything else, they're dangerous in the wrong hands."
The total number of quad bike fatalities this year is now five, the same total as 2016.
Mr Palmer says quad bikes are great machines, but many things need to be considered before using them:
"If you are on steep ground, you have to be very careful… it's usually speed, it's maintenance and the lack of training that cause problems."
Both cases will be referred to the coroner.
"It's a sad situation when people die on farms," says Mr Palmer. "It's a shocking thing… we've got to learn something from it."