Serious complaints against door-to-door sellers has led Consumer NZ to launch a nationwide campaign against the sales tactic.
Chief executive Sue Chetwin said Consumer received regular complaints about "hard-sell" door-to-door sellers.
"We get regular complaints about the hard-sell and exploitative sales tactics these traders use. Many cases involve elderly or vulnerable consumers, pressured to sign up for products they don't want and can't afford," Ms Chetwin said.
"We've dealt with cases involving elderly people sold $3000 vacuum cleaners that clean no better than vacuums you can buy for $100. We've also dealt with complaints from consumers pressured to buy grossly overpriced beds and other household goods they couldn't afford and had to go into debt to purchase," she said.
As part of its campaign, Consumer is distributing free "Do Not Knock" stickers and calling for changes to the Fair Trading Act to make it an offence for sellers to ignore the sign.