The black market for New Zealand's most popular chocolate milk could soon be shut down.

Photos were posted online yesterday, seeming to show counterfeits of the much-hyped Lewis Road Creamery chocolate being sold.

Company spokeswoman Angela Weeks says they're looking into the claims of counterfeits, and are closing in on the source.

Real versions are still being sold on TradeMe, for well above the retail price of $6, some bottles going for more than $20.