The ungrateful or unsatisfied are already inundating Trade Me with Christmas presents they don't want, the website says.
The site, which allows people to advertise new or second-hand goods for sale, said the listings were rolling in.
A survey of more than 600 people, the site said, found almost half of respondents had "unwrapped a clanger" at some point.
The gifts most commonly rejected included clothing, homeware and housework products, like vacuum cleaners.
However, not all unwanted gifts went on sale, the survey found. 41 percent of respondents said they had no problem re-gifting an unwanted present.