The message 'don't knock' is being hammered home today in a part of Auckland where dodgy dealers are a problem.

The Mangere Community Law Centre and Consumer New Zealand are distributing 10 thousand stickers and letters in Mangere.

MP Su'a William Sio says it's about encouraging people to say no to door-to-door salesmen and clothing trucks.

"Recognising that there is a better way of buying your goods, rather than from your door-to-door salespeople or these trucks which offer up goods at exorbitant prices," he says.