Tomy's Harry Potter Voice Activated Wand Torches were averaging 500 units per week, but since the release of the final instalment of the series, demand has increased to 2,500.
The other big seller is The Monster Book of Monsters (pictured), which is being advertised before cinema screenings of the films.
Alison Free, brand manager for the boys ranges at Tomy, said: "Because the Dealthy Hallows Part 2 is the last in the series, Potter fans are making sure they snap up as many of the toys as possible so they have mementoes to go along with their memories of the films.
"We always knew the film was going to have a significant impact on sales, but the figures are incredible."
Tomy's licence also includes action figures and dueling magic wands.
Free added: "With the DVD released in November, we’re expecting our Harry Potter range to be one of the stand out successes of Christmas 2011."