The Fire Service is concerned about some fireworks retailers operating outside the law.
Official figures show a doubling of fireworks imports compared to last year, to more than 1100 tonnes.
Some retailers report there has been a proliferation of roadside stalls.
The Department of Labour, which is responsible for policing the sale of fireworks, says it is following up some complaints.
Fire Service national commander Mike Hall says he's worried about the dangers of what he calls back-street vendors.
He says the service has already had 28 fireworks-related callouts since the the fireworks went on sale on Tuesday.