TRENTON - New Jersey Lottery officials are warning Pick 6 Lotto winners about a scam that promises additional prizes.

Officials are investigating unsolicited calls in which a person claiming to be a lottery employee tells of a promotion in which past Pick 6 jackpot winners are randomly selected for additional prizes. The person says the past winner must make a prepayment before a larger sum can be given, officials said.

"It has never been - nor will it ever be - the policy of the New Jersey Lottery to ask for a 'prepayment' before sending out any prize," William T. Jourdain, acting executive director of the lottery, said in a statement. "This scam, unfortunately, is just one of the latest scams that our security unit has seen throughout the international gaming community."

Spokesman Dominick DeMarco said that there was no list of past winners online, but that the lottery did put out news releases when winners came forward.

Jourdain said the agency's security unit was looking into all possibilities in its investigation, which DeMarco said started "fairly recently." Officials are asking that any past winner who receives a suspicious call contact the lottery's security unit at 609-599-5806.