The decline is being blamed on the popularity of organised displays.
Environment and ACC Minister Nick Smith said imports of fireworks into New Zealand had plummeted, from 1763 tonnes in 2006 to about 500 tonnes this year.
People were choosing to attend large public displays, instead of holding their own smaller ones at home, he told The Dominion Post.
ACC claims for injuries related to fireworks had also dropped in the last three years, from 473 in 2006 to 290 last year, he said.
"I will be looking pretty closely post-Guy Fawkes 2009 and reviewing whether we are taking the more dangerous and stupid edges off people's behaviour."
Two years ago, new regulations confined sales to four days, from November 2 to November 5, and allowing only those over 18 to buy them. Previously, anyone over 14 could purchase them for the 10 days leading up to Nov 5.
The Society for the Protection for Animals (SPCA) today advised pet owners to keep their animals indoors, in a safe, quiet place.
"Many animals experience fear and distress caused by the sounds, smells and bursts of light that fireworks produce," it said.
The organisation advised making a safe place for pets to go during fireworks displays.
It also advised feeding dogs a big, heavy, high-carbohydrate meal of pasta, potatoes or overcooked rice in the late afternoon, to make them sleepy in the evening.
