Small 'hand' tractor sales were also down 21 percent to 596 units in January 2014, from 763 a year earlier.
In January 2012, 1,675 small tractors were registered.
Large tractor sales were down 42 percent to 180 units in January 2014 from a year earlier.
Two years ago in January 546 units were sold.
Tractors are sold in agricultural regions, which have seen droughts.
JB Stockbrokers says tractors are also used for goods transport and the increasing availability of mini trucks may be displacing them.
However there has been some recovery in the passenger vehicles sector. Car registrations were up 35 percent to 1,949 in January 2014 from a year earlier, though down from the 5000 plus units a month seen in the pre-tax hike days.
Motor cycle sales also picked up 17 percent to 16,402 units in January 2014 from a year earlier though down from the 20,000 units plus a month seen in pre tax hike days.
An analysis by JB Stockbrokers showed that mini truck (less than one tonne) registra