Two washing machines which had been recalled have exploded in Waikato this week.
The Samsung top loader models were recalled in 2013 due to risk that water could get into the electrical system and cause a fire.
Fire Service fire investigations manager Peter Wilding told Fairfax when they were recalled there were about 34,000 affected machines in use.
Most of them had been recalled, but 4000 were still remaining.
"In the last four years some of those may have been tossed out," Wilding told Fairfax.