Kiwis who play foreign lotteries have been warned they may not be able to claim any winnings.
At least three companies offer European lottery tickets in New Zealand - The European Lottery Guild, SKL and Boesche.
The former is offering $30 tickets in the Euro Millions lottery through a mailshot,
and advertising jackpots of up to $390 million.
Ministry of Consumer Affairs spokesman Richard Parlette said while the lotteries were genuine, they would advise consumers to "tread very carefully".
Parlette said the true entry fee was much more than the ticket's face value, meaning the buyer would be part of a syndicate and share any winnings.
Because most government- backed lotteries can only be played by that country's residents, overseas winners may never be able to claim the jackpot, he said.
The European Lottery Guild website said its mission was to allow overseas customers to enjoy foreign lotteries "from the comfort of their own home".
It said administration costs were covered in the ticket price, so nothing further was deducted from winnings.
Spokeswoman Gloria Evans said all buyers were sent documents confirming their tickets, and none had experienced difficulty claiming prizes.
She said there were many lottery scams operating.
The guild actively warned customers on how to spot unscrupulous offers.
