Nationwide, there were more than 300,000 searches for unwanted gifts from December 25 to 28.
He said there were millions of dollars worth of unwanted gifts floating around homes.
"Trade Me has an important part to play in extending the lives of those items, getting them out of Kiwis' wardrobes and rubbish bins, and into the hands of people who will use them and appreciate them more."
Mr Mudge said New Zealanders should tread with care when deciding whether to pass unwanted gifts on to someone they know.
"As recently as this month, TV host and comedian John Oliver noted the pitfalls and issues with regifting, including the major faux pas of giving it back to the person who sent it to you.
"If you choose to sell it, tread with care on that front too - take special care not to identify the giver in your description and avoid sharing it on social media. You can never tell who will see your ad."
Trade Me had a dedicated unwanted gift section to make it easy for members to find and buy unwanted items.
Unusual unwanted gifts on Trade Me on Boxing Day included someone else's Christmas card, a Storm Trooper Cookie Jar and a Star Wars thumb wrestling book.