''During winter, we get at least one complaint every week from people who are concerned about the quality or quantity of firewood they have received,'' Dunedin CAB manager Ngaire Duke said.
Problems most often arose when people bought wood from a non-certified firewood seller, she said.
''People will find cheap wood and have it delivered, but it can turn out to be the wrong size, or less than they thought they were getting,'' she said.
In conjunction with the Ministry of Consumer Affairs, Citizens Advice Bureaus around New Zealand were monitoring the sale of firewood this winter and could offer advice, Mrs Duke said.
Dunedin Firewood, owned by Warren and Debbie Michelle, regularly heard from people who had had a bad experience with ''fly-by-night'' wood-sellers and advised people to stick with the professionals.
''We pride ourselves on being honest woodies, but there are a few too many back-street boys out there,'' Mr Michelle said.
Reputable wood merchants adhered to strict firewood quality standards and measures.
''We encourage people to come into our yard and see what we are offering before they buy,'' he said.
Woodland Products manager Mike Rogan said people who dealt with wood merchants who were trade certified could be assured they were getting what they paid for.
''We often hear from people who have had problems with wood - there are a lot of cowboys out there,'' Mr Rogan said.
''People see it [selling wood] as an easy way to make money.''
People should not buy wood on price alone, as there were many factors to consider, including its moisture content and measure. It was hard for reputable merchants to compete on price with people who were not paying overheads or tax, but quality was just as important, he said.
''It is also useful if people don't have a preconceived notion about only buying a particular type of wood,'' Mr Rogan said.
''Wood merchants can steer them in the right direction.''
Along with monitoring wood sales, the Citizens Advice Bureau has been contracted to provide assistance with the Whats My Number power switch programme again this year.
People who would like to know if they were paying too much for their electricity, but were unsure of how to find out through the WhatsMyNumber.org.nz website would be welcome to bring a power bill into the Dunedin Citizens Advice Bureau for advice, Mrs Duke said.
