A Dunedin supermarket that sold fireworks before it was legally allowed apologised for the "mistake'' yesterday.
The Environmental Protection Authority allows retailers to sell or display fireworks for four days before and including Guy Fawkes Day.
The period this year begins tomorrow and ends on Saturday.
Countdown spokesman James Walker said Countdown Mailer Street in Mornington "made a mistake'' on Sunday and displayed fireworks in the supermarket for about 30 minutes.
During the time, one pack of sparklers was sold.
As soon as supermarket staff realised the error, the fireworks were removed from display, he said.
Countdown had "proactively alerted'' the authority about the sale.
"We apologise to customers for this error.''
Countdown had strict instructions about the safe storage, display and sale of fireworks, and it reinforced the importance of those instructions with its staff yesterday, he said.