Hawai'i residents are being warned about a possible telephone scam by a man who poses as a state Department of Health worker and offers $1,000 gift cards or free insurance in return while seeking personal information.

Calls have been made to people on O'ahu and the Big Island during the past three months, Heath Department spokeswoman Janice Okubo said. Suspicious residents contacted the department after receiving the calls, and police in Honolulu and the Big Island were notified.

Over the past several years police and consumer groups have warned of similar telephone scams in which Hawai'i residents receive calls from people trying to gain Social Security numbers, bank account or credit card information. The schemes have included identity thieves pretending to be bank employees and contest directors that require information to process a refund or prize.

"Even when we do survey work for the department we may ask for ethnic background or the number of people in the family, but never their Social Security number or date of birth," Okubo said.

People who are unsure about survey calls from the Health Department can check their authenticity by telephoning the department at 586-4400 on O'ahu, Okubo said.

On the Big Island they can call 974-6006 and on Maui 984-8200. Kaua'i residents can telephone 241-3514.