Retailers say many people are bulk-buying conventional lightbulbs before they are phased out.
The Government announced in June it will phase out what it calls "inefficient lightbulbs" from October next year, in favour of ones which use less power.
New energy efficiency standards are to be introduced.
Wellington lighting retailer Allan McWilliams, who runs a shop called the Lightbulb Man, says demand for standard incandescent bulbs has soared since the policy was announced.
He says customers are buying boxes of standard lightbulbs as well as other types as they fear those will soon disappear from shop shelves.
Mr McWilliams says many people are confused. Others are concerned about the mercury content of eco-bulbs and recent reports that they overheat.
He says many shoppers do not want to be forced into buying an inferior lightbulb.
Energy Minister David Parker says the policy is widely misunderstood and he is at a loss to explain the growing myths around it.
But National's Gerry Brownlee says the policy is a de facto ban on conventional lightbulbs.
The Energy Efficiency and Conservation Authority is highly sensitive about the issue. The agency insists the Government has no plans to make it mandatory to use ecobulbs.