Lingerie, fishing gear and phone cards are among unwanted Christmas gifts Northlanders are trying to offload on Trade Me.
Trade Me spokesman Logan Mudge said women in Northland and nationwide were selling lingerie they weren't too keen on.
One Northland seller was auctioning a set of florescent briefs on the "Unwanted Xmas Gifts" section of the website.
She described them as being even brighter than they looked in the photo she provided.
Mr Mudge said there were also a lot of prepaid phone vouchers for sale in Northland.
"We also saw a lift in fishing equipment so maybe some Northlanders got some tackle they didn't need," he said.
Northland's Trade Me listings were up 8 per cent, this year on last year, for the December 25 to 28 period. Sales were up 5 per cent.
Mr Mudge said Trade Me experienced a huge spike in searches and activity each Boxing Day as New Zealanders got busy trading items that didn't fit, were deemed uncool or were unfortunate double-ups.
Nationwide, there were more than 300,000 searches for unwanted Christmas gifts from December 25 to 28.
Mr Mudge said there were millions of dollars worth of unwanted gifts floating around .
"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 on unwanted gifts to someone they know. "As recently as this month, TV host and comedian John Oliver noted the pitfalls and issues with re-gifting, including the major faux pas of giving it back to the person who sent it to you," he said.
"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 section for unwanted gifts.
-Do you think it's okay to sell unwanted Christmas gifts? Let us know your thoughts at letters@northernadvocate.co.nz